JP5847005B2 - Eddy current flaw detection system and eddy current flaw detection method - Google Patents

Description

  The present invention relates to an eddy current flaw detection system and a eddy current flaw detection method, and more particularly to an eddy current flaw detection system and a eddy current flaw detection method that can prepare signals indicating tube ends in flaw detection data of a plurality of tubes.

  A large number of heat transfer tubes are regularly arranged in the heat exchanger of the power plant. The heat transfer tube has a straight tube shape or a U shape, and both ends are fixed by tube plates in the heat exchanger. The length of the heat transfer tube is several tens of meters, and a support plate is arranged to suppress vibration.

  In the heat transfer tube inspection, the probe is once inserted into the tube, and then the probe cable is pulled out and scanned to obtain a flaw detection waveform (flaw detection signal). Generally, as a flaw detection waveform, two signal waveforms of an in-phase (X) component and a different phase (Y) component that is 90 ° out of phase with respect to a certain reference signal (sine wave signal) are acquired. The inspector determines whether or not there is a defect by determining the threshold value of these amplitudes. Alternatively, Lissajous corresponding to two waveform trajectories is evaluated to improve the determination accuracy (see, for example, Patent Document 1).

JP 2002-296241 A

  In the eddy current flaw detection apparatus disclosed in Patent Document 1, the burden on an inspector confirming flaw detection data is reduced by evaluating Lissajous and improving the determination accuracy. However, this eddy current flaw detector does not reduce the burden when checking flaw detection data of a plurality of tubes.

  On the other hand, in order to reduce the burden of checking the flaw detection data of a plurality of tubes, it is assumed that the flaw detection data of the plurality of tubes is displayed in a two-dimensional display and visually confirmed.

  In that case, it is required to display the flaw detection data of a plurality of pipes corresponding to the position of the structure by a signal serving as a position reference.

  An object of the present invention is to provide an eddy current flaw detection system and an eddy current flaw detection method that can reduce the burden on an inspector confirming flaw detection data of a plurality of tubes.

  (1) In order to achieve the above object, the present invention is an eddy current flaw detection system for detecting defects in a plurality of tubes, in which an eddy current is induced in the tube and a change in the induced eddy current is detected. A flaw detection coil, a probe having a reference part sensor that outputs a reference signal corresponding to a reference part representing a part where the structure of the tube changes, an eddy current flaw detector for flaw detection by applying an excitation voltage to the flaw detection coil, The reference part in the flaw detection data of the plurality of pipes based on a reference signal output from the insertion / extraction part that inserts the probe into the pipe and pulls out the inserted probe from the pipe and the reference part sensor A data array device that shifts the flaw detection data so as to prepare signals indicating the above and a display device that two-dimensionally displays the flaw detection data of the plurality of shifted tubes.

  As a result, the inspector can check the presence / absence of defects while comparing the flaw detection data of a plurality of tubes, which are aligned based on the position of the reference portion, so check flaw detection data of a plurality of tubes. The burden on the occasion is reduced.

  (2) In the above (1), preferably, the data array device measures position data indicating a position of the probe while the probe is pulled out of the tube by the insertion pulling unit, and the insertion pulling unit While the probe is withdrawn from the tube, flaw detection is performed from a change in eddy current detected by the flaw detection coil, and flaw detection data and measured probe position data are stored in association with each other and output from the reference region sensor. Based on the reference signal, the reference portion of the tube is detected, the probe position data measured when the reference portion of the tube is detected is stored, and measured when the reference portion of the tube is detected. Based on the position data of the probe, the flaw detection data is simulated so that signals indicating the reference site are prepared in the flaw detection data of the plurality of tubes. It is obtained so as to door.

  As a result, the inspector can check the presence / absence of defects while comparing the flaw detection data of a plurality of tubes, which are aligned based on the position of the reference portion, so check flaw detection data of a plurality of tubes. The burden on the occasion is reduced.

  (3) In the above (2), preferably, the reference part sensor includes a light detector that detects light, and the light detector detects the reference part of the tube based on a change in the detected light amount. A corresponding reference signal is output.

  Thereby, when the outside of the tube is bright, the reference site sensor can detect the reference site of the tube.

  (4) In the above (3), preferably, the probe further includes a light source, and the photodetector detects a change in reflected light reflected by the surface of the tube. Based on this, a reference signal corresponding to the reference portion of the tube is output.

  Thereby, when the outside of the tube is dark, the reference region sensor can detect the reference region of the tube.

  (5) In the above (4), preferably, the reference part sensor detects an end of the tube as a reference part of the tube.

  Thus, the data array device can reliably prepare signals indicating the reference portion in the flaw detection data based on the position of the tube end where the reference signal changes greatly.

  (6) In the above (1), preferably, the reference site sensor includes an optical fiber, one end of the optical fiber is disposed on an outer periphery of the probe, and the eddy current flaw detection system further includes the light An optical signal that is taken in from one end of the fiber and that is output from the other end of the optical fiber is converted into an electrical signal, and the electrical signal is output to the data array device as a reference signal. is there.

  This eliminates the need for power supply wiring for the reference site sensor.

  (7) In the above (1), preferably, the reference part sensor includes an eddy current flaw sensor that induces an eddy current in the tube and detects a change in the induced eddy current, and the eddy current flaw sensor Is configured to output a reference signal corresponding to the reference portion of the tube based on the detected change in eddy current.

  Thereby, the reference | standard site | part sensor can detect a pipe end as a reference | standard site | part of a pipe | tube.

  (8) In order to achieve the above object, the present invention is an eddy current flaw detection method for detecting defects in a plurality of tubes, in which eddy current is induced in the tube and a change in the induced eddy current is detected. Insertion / extraction for inserting a probe having a flaw detection coil and a reference part sensor that outputs a reference signal corresponding to a reference part representing a part where the structure of the pipe changes into the pipe, and pulling out the inserted probe from the pipe And a shift step of shifting the flaw detection data so as to align signals indicating the reference portion in the flaw detection data of the plurality of tubes based on the reference signal output from the reference portion sensor, and a plurality of shifted A display step of displaying the tube flaw detection data two-dimensionally is provided.

  As a result, the inspector can confirm the flaw detection data of a plurality of tubes prepared with reference to the position of the reference portion as a reference, so that the burden of checking flaw detection data of a plurality of tubes is reduced. It is reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the burden at the time of an inspector confirming the flaw detection data of a some pipe | tube can be reduced.

1 is a schematic configuration diagram of an eddy current flaw detection system according to a first embodiment of the present invention. It is a schematic block diagram of the probe which is the 1st Embodiment of this invention. It is a figure for demonstrating the use condition of the structure of a heat exchanger, and an eddy current flaw detection system. It is a flowchart which shows operation | movement of the eddy current flaw detection system which is the 1st Embodiment of this invention. It is a timing chart for demonstrating a flaw detection signal and a reference signal. It is a figure for demonstrating the process which calculates | requires the determinant which shifts a flaw detection signal from the determinant of a reference signal. It is a figure which shows the transition of a flaw detection signal. It is a figure which shows the correspondence of the position of the probe in a heat exchanger tube, and a flaw detection signal. It is a schematic block diagram of the eddy current flaw detection system which is the 2nd Embodiment of this invention. It is a schematic block diagram of the probe which is the 2nd Embodiment of this invention. It is a schematic block diagram of the eddy current flaw detection system which is the 3rd Embodiment of this invention. It is a schematic block diagram of the probe which is the 3rd Embodiment of this invention.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of an eddy current flaw detection system according to a first embodiment of the present invention. The eddy current flaw detection system includes a probe 101, an insertion / extraction machine 102, an eddy current flaw detector 103, a signal amplifier 104, an A / D converter 105, a data array device 106, and a display device 107. Here, the eddy current flaw detection system is a system that detects a defect in a tube group such as a heat transfer tube used in a heat exchanger. Details of the configuration of the heat exchanger will be described later with reference to FIG.

  The probe 101 supplies a voltage signal based on a change in eddy current induced in the heat transfer tube to the eddy current flaw detector 103. The probe 101 supplies a reference signal corresponding to a reference portion (for example, a tube end, details of which will be described later with reference to FIG. 3) to the signal amplifier 104. The probe 101 and the eddy current flaw detector 103 are electrically connected. The probe 101 and the signal amplifier 104 are electrically connected. Details of the configuration of the probe 101 will be described later with reference to FIG.

  In response to the instructor's instruction, the insertion / extraction machine 102 extracts the cable 203 connected to the probe 101 at a constant speed, and extracts the probe 101 from the heat transfer tube. The inspector inserts the probe 101 into the heat transfer tube by pulling out the cable 203 pulled out by the insertion / extraction machine 102 and sending it out by hand or by sending the probe 101 into the tube with compressed air from an air gun. To do.

  The eddy current flaw detector 103 supplies (applies) an alternating voltage (excitation voltage signal) having a predetermined frequency to the probe 101. Further, the eddy current flaw detector 103 separates the flaw detection signal into the X component of the in-phase component and the excitation voltage signal and the Y component of the out-of-phase component by detecting the phase of the flaw detection signal supplied from the probe 101, The separated X component and Y component of the flaw detection signal are supplied to the A / D converter 105, respectively. The eddy current flaw detector 103 and the A / D converter 105 are electrically connected.

  The signal amplifier 104 amplifies the reference signal supplied from the probe 101 and supplies the amplified reference signal to the A / D converter 105. The signal amplifier 104 and the A / D converter 105 are electrically connected.

  The A / D converter 105 converts the analog flaw detection signal (separated into X and Y components) supplied from the eddy current flaw detector 103 and the analog reference signal supplied from the signal amplifier 104 into a digital flaw detection signal. And the converted digital flaw detection signal and the reference signal are supplied to the data array device 106. The A / D converter 105 and the data array device 106 are electrically connected.

  The data array device 106 includes, for example, a PC (Personal Computer) including a control unit such as a processor, a storage unit such as a memory, a time measuring unit such as an RTC (Real Time Clock), and an operation unit such as a keyboard. When the control unit executes a predetermined program stored in the storage unit, the data array device 106 associates the flaw detection signal supplied from the A / D converter 105 with the time (timing) when the flaw detection signal is supplied. In addition, each heat transfer tube is stored in the storage unit, and based on the reference signal supplied from the A / D converter 105, the flaw detection signal (flaw detection data) stored in the storage unit is detected at the timing when the reference part is detected. The function of aligning as a reference and supplying image information of the prepared flaw detection data to the display device 107 is realized. The data array device 106 and the display device 107 are electrically connected by a video cable. In addition, the data array device 106 notifies the insertion / extraction machine 102, the eddy current flaw detector 103, and the like of the instruction from the inspector input by the operation unit. Details of the function of the data array device 106 will be described later with reference to FIG.

  The display device 107 displays the flaw detection signals of one heat transfer tube based on the image information supplied from the data array device 106, or displays the flaw detection signals of a plurality of tubes side by side.

  FIG. 2 is a schematic configuration diagram of the probe 101 according to the first embodiment of the present invention. The probe 101 includes a first flaw detection coil 201a, a second flaw detection coil 201b, a photodetector 202, a cable 203, and a probe housing 204.

  The first flaw detection coil 201 a and the second flaw detection coil 201 b are configured by winding one conductive wire around the outer periphery of the central portion of the probe 101. The first flaw detection coil 201a and the second flaw detection coil 201b are spaced apart from each other at the center of the probe 101. The first flaw detection coil 201a and the second flaw detection coil 201b are each connected to the connector terminal of the eddy current flaw detector 105, and supplied with an excitation voltage signal. Due to this magnetic field, an eddy current is generated in the heat transfer tube.

  On the other hand, an induced current is generated in the first flaw detection coil 201a and the second flaw detection coil 201b by a change in eddy current. The first flaw detection coil 201a and the second flaw detection coil 201b supply the eddy current flaw detector 103 with an induced current (flaw detection signal) generated by a change in eddy current (self-inductive self-comparison type).

  The photodetector 202 includes a photodiode or the like, detects electromagnetic energy of light, and supplies an electric signal (reference signal) corresponding to the detected energy to the signal amplifier 104. The photodetector 202 functions as a reference part sensor that outputs a reference signal corresponding to the reference part. The photodetector 202 includes a first surface S1 that is perpendicular to the axis of the first flaw detection coil 201a and contacts the first flaw detection coil 201a, and is close to the second flaw detection coil 201b, and a second flaw detection coil 201b. On the intersection line of the third surface S3 having the same distance from the second surface S2 close to the first flaw detection coil 201a and the outer peripheral surface of the probe 101 out of the surfaces perpendicular to the axis and in contact with the second flaw detection coil 201b Is arranged. As a result, a flaw detection waveform centering on the timing at which the reference signal greatly changes in the reference portion is obtained.

  The cable 203 includes the wiring of the first flaw detection coil 201a and the second flaw detection coil 201b and the wiring of the photodetector inside. The wiring of the first flaw detection coil 201a and the second flaw detection coil 201b is composed of two coaxial lines, and transmits an excitation voltage signal from the eddy current flaw detector 103 to the first flaw detection coil 201a and the second flaw detection coil 201b. . On the other hand, the wiring of the photodetector 202 is composed of two coaxial lines, and transmits a reference signal from the photodetector 202 to the signal amplifier 104.

  The probe housing 204 is made of, for example, a resin molded into a substantially cylindrical shape. The wiring included in the cable 203 is connected to the first flaw detection coil 201a, the second flaw detection coil 201b, and the photodetector 202, and a resin is poured into the probe housing 204 to be solidified and joined to the cable 203.

  Next, the operation of the eddy current flaw detection system according to the first embodiment will be described. Hereinafter, the case where the eddy current flaw detection system inspects the heat transfer tubes constituting the heat exchanger will be described as an example. In this embodiment, it is assumed that the outside of the heat transfer tube is bright.

FIG. 3 is a diagram for explaining the configuration of the heat exchanger 1000 and the usage status of the eddy current flaw detection system. The heat exchanger 1000 to be inspected by the eddy current system includes a plurality of heat transfer tubes 1001 (tube group), a tube plate 1002 and a support plate 1003 (1003 _{1 to} 1003 ₃ ). The plurality of heat transfer tubes 1001 are configured by a substantially cylindrical metal tube. Tube plate 1002 is formed of a substantially disk-shaped metal plate, and includes a plurality of holes that fit into the tube ends of heat transfer tube 1001. The support plate 1003 is made of a substantially disk-shaped metal plate and includes a plurality of holes for fixing the heat transfer tube 1001. When the heat transfer tubes 1001 pass through these holes, vibration of the plurality of heat transfer tubes 1001 is suppressed. The plurality of heat transfer tubes 1001 are fixed substantially in parallel by a tube plate 1002 and a support plate 1003. In this heat exchanger 1000, the heat transfer tube 1001 has a straight tube shape, but is bent into a U shape in the middle of the heat transfer tube 1001, and both ends of the heat transfer tube 1001 are fitted to one tube plate 1001. There is also. Here, the tube end of the heat transfer tube 1001, the portion where the heat transfer tube 1001 is in close contact with the support plate 1003, the portion where the heat transfer tube 1001 is in close contact with the tube plate 1002, and the portion bent in a U shape in the middle of the heat transfer tube 1001 In addition, a portion where the structure of the heat transfer tube 1001 is changed is a reference portion, and the tube end is mainly used as a reference.

  As shown in FIG. 3, the inspector uses the insertion / extraction machine 102 to sequentially insert the probes 101 into the heat transfer tubes 1001 of the heat exchanger 1000 and inspect the heat transfer tubes 1001.

  FIG. 4 is a flowchart showing the operation of the eddy current flaw detection system according to the first embodiment of the present invention. First, the inspector places the probe 101 at one end of the heat transfer tube 1001 (on the right side in FIG. 3), and sends the cable 203 into the tube by hand. Thereby, the probe 101 connected to the cable 203 is inserted into the heat transfer tube 1001.

  Next, the inspector instructs the insertion / extraction machine 102 to extract the cable 203 using the operation unit of the data array device 106. The insertion / extraction machine 102 extracts the cable 203 at a constant speed in response to an instruction from the inspector. As a result, the probe 101 moves from one of the heat transfer tubes to the other at a constant speed.

  In this way, the eddy current flaw detection system inserts the probe 101 into the heat transfer tube 1001, and pulls out the inserted probe 101 from the heat transfer tube 1001 (step S10 in FIG. 4).

  The eddy current flaw detector 103 supplies (applies) an excitation voltage signal to the first flaw detection coil 201a and the second flaw detection coil 201b of the probe 101 in response to the insertion / extraction machine 102 starting winding of the cable 203. )

  The first flaw detection coil 201a and the second flaw detection coil 201b of the probe 101 generate a magnetic field based on the supplied excitation voltage signal. Thereby, an eddy current is generated in the heat transfer tube 1001. On the other hand, an induced current is generated in the first flaw detection coil 201a and the second flaw detection coil 201b by a change in eddy current. The first flaw detection coil 201 a and the second flaw detection coil 201 b supply the generated induced current (flaw detection signal) to the eddy current flaw detector 103.

  The photodetector 202 of the probe 101 supplies light from the surroundings to the signal amplifier 104 as an electrical signal (reference signal).

  The signal amplifier 104 amplifies the supplied reference signal and supplies the amplified reference signal to the A / D converter 105.

  The A / D converter 105 converts the analog flaw detection signal supplied from the eddy current flaw detector 103 and the analog signal supplied from the signal amplifier 104 into a digital flaw detection signal and a reference signal at a predetermined clock timing. The converted digital flaw detection signal and reference signal are supplied to the data array device 106.

  FIG. 5 is a timing chart for explaining the flaw detection signal and the reference signal. In the following, in order to simplify the description, it is assumed that there is no tube plate 1002 and only one support plate is described. In addition, the horizontal axis of FIGS. 5B to 5F indicates time, and time advances in the right direction of each figure. Here, since the probe 101 is extracted from the heat transfer tube 1001 at a constant speed by the insertion / extraction machine 102, the time represented by the horizontal axis in FIGS. 5 (B) to 5 (F) is shown in FIG. 5 (A). This corresponds to the position of the probe 101 in the heat transfer tube 1001.

  The vertical axis in FIG. 5B indicates the voltage value of the clock (clock pulse) when the A / D converter 105 performs A / D conversion. The voltage value of the clock pulse repeats a high level voltage value and a low level voltage value at a constant cycle. The clock pulse is a digital signal.

  The vertical axis in FIG. 5C indicates the voltage values of the acquisition start signal Sig1 that is a trigger for starting the storage of the flaw detection signal and the acquisition end signal Sig2 that is a trigger for ending the storage of the flaw detection signal. In FIG. 5C, as an example, the acquisition start signal Sig1 and the acquisition end signal Sig2 are indicated by rectangular waves. The acquisition start signal Sig1 and the acquisition end signal Sig2 are digital signals.

  The vertical axis in FIG. 5D indicates the voltage value of the X component of the flaw detection signal obtained by phase detection. The vertical axis in FIG. 5E indicates the voltage value of the Y component of the flaw detection signal obtained by phase detection. Note that the X component and the Y component of the flaw detection signal are analog signals.

  The vertical axis of FIG. 5F schematically shows the voltage value of the reference signal output from the photodetector 202. The reference signal is an analog signal.

  Hereinafter, the flaw detection signal and the reference signal will be described with reference to FIGS. 5 (A) to 5 (F).

  The voltage signals output from the first flaw detection coil 201a and the second flaw detection coil 201b are phase-detected by the eddy current flaw detector 103, so that the X component of the in-phase component, the excitation voltage signal, and the out-of-phase component of the excitation voltage signal are detected. Divided into Y components. The X component and the Y component of the flaw detection signal vary greatly at the tube end of the heat transfer tube 1001 as shown in FIGS. These flaw detection signals X1, X3 and flaw detection signals Y1, Y3 are signals corresponding to the tube ends. Further, the X component and the Y component of the flaw detection signal change slightly in the portion where the heat transfer tube 1001 is the support plate 1003. The flaw detection signal X2 and the flaw detection signal Y2 are signals corresponding to the support plate 1003.

  On the other hand, the reference signal output from the photodetector 202 varies greatly at the tube end of the heat transfer tube 1001 as shown in FIG. When the light detector 202 is outside the heat transfer tube 1001, the periphery of the light detector 202 is bright, and when the light detector 202 is inside the heat transfer tube 1001, the light detector 202 is dark. is there. In FIG. 5F, the reference signal (analog) is schematically represented.

  The flaw detection signal and the reference signal are converted from an analog signal to a digital signal at a clock timing shown in FIG. Further, in response to an inspector's instruction, as shown in FIG. 5 (C), the acquisition start signal Sig1 for starting the storage of the flaw detection signal (the left rectangular signal in the event of FIG. 5 (C)) and the flaw detection signal are stored. Capture end signal Sig2 (right rectangular signal in the event of FIG. 5C) is generated. Details of these operations will be described later.

  The A / D converter 105 converts the analog flaw detection signal supplied from the eddy current flaw detector 103 and the analog reference signal supplied from the signal amplifier 104 into a digital flaw detection signal at the clock timing shown in FIG. And the converted digital flaw detection signal and the reference signal are supplied to the data array device 106. The data array device 106 generates image information of the flaw detection signal based on the flaw detection signal supplied from the A / D converter 105, and supplies the generated image information of the flaw detection signal to the display device 107. The display device 107 displays a flaw detection signal of the heat transfer tube 1001 being inspected based on the image information supplied from the data array device 106.

  The inspector places the probe 101 at the scanning start position, and instructs the data array device 106 to start storing the flaw detection signals using the operation unit of the data array device 106. At this time, as shown in FIG. 5C, the data array device 106 generates a capture start signal Sig1 for starting storage of the flaw detection signal.

  The data array device 106 responds to the acquisition start signal Sig1 for starting the storage of the flaw detection signal, and the digital flaw detection signal supplied from the A / D converter 105 and the time t acquired from the time measuring unit (storage of the flaw detection signal). The time from the start of the process is associated and stored in the storage unit. Here, since the insertion / extraction machine 102 pulls out the cable 203 at a constant speed, the time t after the start of the storage of the flaw detection signal is the position of the probe 101 in the heat transfer tube 1001 when the storage of the flaw detection signal is started. Corresponding to The data array device 106 acquires the flaw detection signal via the eddy current flaw detector 103 and the like, and acquires the reference signal via the signal amplifier 104 and the like, but the time delay of the flaw detection signal and the reference signal is relative to the scanning speed. Because it is small enough.

  That is, while the probe 101 is pulled out from the heat transfer tube 1001 by the insertion / extraction machine 102, the data array device 106 measures position data (time t) indicating the position of the probe 101, and is measured as a flaw detection signal (flaw detection data). The position data (time t) of the probe 101 is stored in association with each other. In this way, the eddy current flaw detection system measures position data indicating the position of the probe 101 while the probe 101 is pulled out of the heat transfer tube 1001 by the insertion / extraction machine 102 (step S20 in FIG. 4), and a flaw detection signal (flaw detection). Data) and the measured position data of the probe 101 are stored in association with each other (step S30 in FIG. 4).

  On the other hand, the data array device 106 binarizes the reference signal by determining whether or not the amplitude of the reference signal is greater than or equal to a predetermined threshold. When the binarized reference signal changes, the data array device 106 stores the time k acquired from the timer unit in the storage unit for each heat transfer tube 1001. The time k when the binarized reference signal changes corresponds to the timing when the probe 101 goes out of the tube of the heat transfer tube 1001.

  That is, the data array device 106 detects the tube end as the reference portion based on the time k when the binarized reference signal changes, and as the position data of the probe 101 measured when the tube end is detected. Remember time k. In this way, the eddy current flaw detection system detects the tube end as the reference region based on the reference signal (step S40 in FIG. 4), and the probe position data (time) measured when the tube end is detected. k) is stored (step S50 in FIG. 4).

  The inspector visually confirms that the probe 101 has come out of the tube from the other end of the heat transfer tube 1001 (on the right side in FIG. 5A), or the amplitude of the flaw detection signal displayed on the display device 107. Is greatly changed similarly to the flaw detection signal corresponding to the first tube end, it is determined that the probe 101 has moved out of the other tube end of the heat transfer tube 1001 (the right side in FIG. 5A). After making this determination, the inspector uses the operation unit of the data array device 106 to instruct the data array device 106 to end storage of the flaw detection signal. At this time, as shown in FIG. 5C, the data array device 106 generates an acquisition end signal Sig2 for ending the storage of the flaw detection signal.

  The data array device 106 ends the storage of the flaw detection signal in response to the capture end signal Sig2 that ends the storage of the flaw detection signal.

By repeating such processing for all the heat transfer tubes 1001, the time k _i (i = 1) when the flaw detection signal time series and the reference signal change for each heat transfer tube 1001 _i (i = 1 to n). ˜n) are stored in the storage unit.

  Next, the inspector uses the operation unit of the data array device 106 to instruct the data array device 106 to prepare the flaw detection signals.

In response to the instructor's instruction, the data array device 106 converts the time series of the flaw detection signals of the respective heat transfer tubes 1001 _i (i = 1 to n) into time (N−k _i ) (i = 1 to n, N : Preset value) is shifted in the time axis direction. Thereby, the flaw detection signals of the respective heat transfer tubes 1001 _i (i = 1 to n) are aligned with reference to the tube end positions. Details will be described later with reference to FIG.

  In this way, the eddy current flaw detection system uses the reference portion in the flaw detection signals (flaw detection data) of the plurality of heat transfer tubes 1001 based on the position data of the probe 101 measured when the tube end as the reference portion is detected. The flaw detection data is shifted so that the signals indicating the above are aligned (step S60 in FIG. 4).

For example, in the range of t <N, the display device 107 two-dimensionally displays the prepared flaw detection signals for the heat transfer tubes 1001 _i (i = 1 to n). Thereby, the inspector can easily confirm a flaw detection signal in a desired range.

  In this way, the eddy current flaw detection system two-dimensionally displays flaw detection data of the shifted plurality of heat transfer tubes 1001 (step S70 in FIG. 4).

  Then, the effect of this embodiment is demonstrated using FIGS.

FIG. 6 is a diagram for explaining processing for obtaining a determinant for shifting the flaw detection signal from the determinant of the reference signal. FIG. 7 is a diagram showing the transition of the flaw detection signal. In the following, for the heat transfer tube 1000 _i (i = 1 to n), the X component of the j-th digital flaw detection signal supplied from the A / D converter 105 is X _ij (i = 1 to n, j: natural number). The Y component is Y _ij (i = 1 to n, j: natural number). The jth digital reference signal supplied from the A / D converter 105 is S _ij (i = 1 to n, j: natural number).

A matrix G11 including the reference signal (S _ij ) is shown in FIG. FIG. 7 shows a matrix G14 composed of the X component (X _ij ) of the flaw detection signal and a matrix G15 composed of the Y component (Y _ij ) of the flaw detection signal before the data array device 106 prepares the flaw detection signals.

The data array device 106 determines whether or not the amplitude of the reference signal S _ij is equal to or greater than a predetermined threshold value S ₀ . Data array device 106, if the amplitude of the reference signal S _ij is determined to be a predetermined threshold value S ₀ or more, the reference signal S _ij and 1, when the amplitude of the reference signal S _ij is lower than a predetermined threshold S ₀ The reference signal S _{ij is set} to 0. Thereby, the reference signal _Sij is binarized.

Data array device 106 acquires from the clock unit time k _i when the binarized reference signal changes from 0 to 1, and stores the obtained time k _i in the storage unit. It shows a row example G12 consisting of the time _{k i} in FIG. The data array device 106 calculates a difference (N−k _i ) between a preset value N and the time k _i . A matrix G13 composed of the difference (N−k _i ) is shown in FIG. The data array device 106 shifts the X component (X _ij ) of the flaw detection signal and the Y component (Y _ij ) of the flaw detection signal by this difference (N−k _i ). Accordingly, as shown in FIG. 7, the matrix G14 composed of the X component (X _ij ) of the flaw detection signal transitions to the matrix G16, and the matrix G15 composed of the Y component (Y _ij ) of the flaw detection signal transitions to the matrix G17. To do.

FIG. 8 is a diagram showing a correspondence relationship between the position of the probe and the flaw detection signal in the heat transfer tube 1001. Hereinafter, for convenience of explanation, an example in which the eddy current system inspects _five heat transfer tubes 1001 _{1 to} 10015 ₅ will be described. Further, in the heat transfer tube 1001 _{1-1001 5,} where to begin saving the flaw detection signal, as shown in FIG. 8 (A), it is assumed that variation. In addition, the heat transfer tube 1001 _4, it is assumed that there is a defect, such as scratches and wall thinning. In FIG. 8, there are support plates 1003 _{1 to} 1003 ₄ .

  Since the timing at which the inspector instructs the start of storage of the flaw detection signal differs depending on each heat transfer tube 1001, the position of the probe 101 at the start of storage of the flaw detection signal is as shown in FIG. It differs for each heat tube 1001.

FIG. 8B is a diagram schematically showing the flaw detection signals before being arranged by the data array device 106. Since the position of the probe 101 at the start of storage of the testing signals are different, the time to start saving the flaw detection signal (t = 0) as a reference, in the respective testing signals of the heat transfer tube 1001 _{1-1001 5,} Den The support plate signal indicating the flaw detection signal at the portion where the heat tube 1001 is in close contact with the support plate 1003 and the tube end signal indicating the flaw detection signal at the tube end of the heat transfer tube 1001 are not available. Further, the heat transfer tube 1001 _4, because there are defects such as scratches and wastage, these testing signals, as shown in FIG. 8 (B), appears defect signal indicating the testing signals in the defect portion. Furthermore, the time from the start of data storage to the end thereof (data storage period) differs for each heat transfer tube 1001. Therefore, the support plate signal, the tube end signal, the defect signal, and the like cannot be easily distinguished, and the burden on the inspector confirming the flaw detection signals of the plurality of heat transfer tubes 1001 is large.

  On the other hand, FIG. 8C is a diagram schematically showing the flaw detection signals (rearrangement data) after being arranged by the data arrangement device 106. Since the flaw detection signals are aligned based on the tube end position of the heat transfer tube 1001, the positions where the support plate signal appears are also aligned.

  As described above, according to the present embodiment, the inspector can confirm the presence or absence of a defect while comparing the flaw detection signals of the heat transfer tubes 1001 arranged with reference to the tube end position. For this reason, the burden at the time of confirming the flaw detection signal of the some heat exchanger tube 1001 is reduced.

(Modification)
The probe 101 may include an eddy current flaw detection sensor instead of the photodetector 202 as a reference site sensor. The eddy current flaw detection sensor is constituted by a flaw detection coil or the like, and outputs an electric signal (reference signal) generated by a change in eddy current. In this modification, the first flaw detection coil 201a and the second flaw detection coil 201b are used as eddy current flaw detection sensors. Thereby, the wiring in the probe 101 can be reduced.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 9 is a schematic configuration diagram of an eddy current flaw detection system according to the second embodiment of the present invention. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the present embodiment, it is assumed that the outside of the heat transfer tube 1001 is dark.

  Compared with the first embodiment, the eddy current flaw detection system according to the present embodiment is different in that the probe 701 and the optical excitation / detection device 704 are provided.

  The probe 701 supplies a flaw detection signal to the eddy current flaw detector 103. In addition, the probe 701 supplies a reference signal to the optical excitation / detection device 704. Furthermore, the probe 701 has a light source. Details of the configuration of the probe 701 will be described later with reference to FIG.

  The optical excitation / detection device 704 amplifies the supplied reference signal and supplies the amplified reference signal to the A / D converter 105. Further, the optical excitation / detection device 704 supplies a voltage signal (photoexcitation voltage signal) used for exciting light with the light source to the probe 701.

  FIG. 10 is a schematic configuration diagram of a probe 701 according to the second embodiment of the present invention. The probe 701 includes a light source 805. The light source 805 is configured by an LED (Light Emitting Diode) or the like, and emits light by exciting light with a light excitation voltage signal supplied from the light excitation / detection device 704. The light source 805 includes a first surface S1 that is perpendicular to the axis of the first flaw detection coil 201a and is in contact with the first flaw detection coil 201a, and that is close to the second flaw detection coil 201b, and an axis of the second flaw detection coil 201b. Of the surface perpendicular to the second flaw detection coil 201b and the second surface S2 close to the first flaw detection coil 201a is equal to the outer surface of the probe 101. Has been. Here, the directions of the light source 805 and the photodetector 202 are adjusted so that the light emitted from the light source 805 is not directly detected by the photodetector 202.

  As a result, when the light source 805 is in the tube of the heat transfer tube 1001, the light emitted from the light source 805 is irregularly reflected on the surface (inner peripheral surface) of the heat transfer tube 1001, and the irregularly reflected light is detected by the photodetector 202. The On the other hand, when the light source 805 is outside the heat transfer tube 1001, the irregularly reflected light is not detected by the photodetector 202. For this reason, the electrical signal (reference signal) output from the photodetector at the tube end of the heat transfer tube 1001 changes greatly.

  According to this embodiment, when the outside of the heat transfer tube 1001 is dark, the tube end of the heat transfer tube 1001 can be detected.

  The light source 805 may blink at a constant cycle. In this case, the data array device 106 binarizes the reference signal by determining whether or not the peak value of the reference signal appears at a constant period. Thereby, the pipe end of the heat transfer tube 1001 can be detected regardless of whether or not the outside of the heat transfer tube 1001 is bright.

  Next, a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 11 is a schematic configuration diagram of an eddy current flaw detection system according to the third embodiment of the present invention. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the present embodiment, it is assumed that the outside of the heat transfer tube 1001 is bright.

  Compared with the first embodiment, the eddy current flaw detection system according to the present embodiment is different in that the probe 501 and the light detection device 504 are provided.

  The probe 501 supplies a flaw detection signal to the eddy current flaw detector 103. In addition, the probe 501 supplies an optical signal taken from the periphery of the probe 501 to the light detection device 504. Details of the configuration of the probe 501 will be described later.

  The light detection device 504 converts the supplied optical signal into an electric signal (reference signal) and amplifies it, and supplies the amplified reference signal to the A / D converter 105.

  FIG. 12 is a schematic configuration diagram of a probe 501 according to the third embodiment of the present invention. The probe 501 includes an optical fiber 603. One end of the optical fiber 603 includes a first surface S1 that is perpendicular to the axis of the first flaw detection coil 201a and is in contact with the first flaw detection coil 201a, and is close to the second flaw detection coil 201b, and a second flaw detection coil. Of the surfaces perpendicular to the axis of 201b and in contact with the second flaw detection coil 201b, the third surface S3 having the same distance from the second surface S2 close to the first flaw detection coil 201a and the outer peripheral surface of the probe 101 It is arranged on the line. As a result, the flaw detection signal also changes greatly at the same timing as when the optical signal changes greatly at the tube end of the heat transfer tube 1001. The other end of the optical fiber is connected to the light detection device 504.

  According to the present embodiment, since the probe 101 does not have the photodetector 202, it is not necessary to provide the reference signal electrical wiring for the probe 101 and the cable 203.

(Modification)
The probe 101 may include a plurality of optical fibers 603, and one ends of the optical fibers 603 may be arranged at equal intervals on the intersection line between the surface S3 and the outer peripheral surface of the probe 101 described above. Thereby, when the probe 101 comes out of the tube from the inside of the tube, the light outside the tube is surely taken in from one end of the optical fiber 603 arranged on this intersection line.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. It is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. Each of the above-described configurations, functions, processing units, processing units, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  In the first to third embodiments, the case where the reference portion is the tube end has been described as an example. However, the reference portion is a portion where the heat transfer tube 1001 is in close contact with the tube plate 1002, and U in the middle of the heat transfer tube 1001. It may be a portion bent into a letter shape.

  In the first to third embodiments, the data array device 106 stores the flaw detection signal and the time from the start of the flaw detection signal in association with each other, and stores them in the storage unit. Based on the speed at which 203 is pulled out, the flaw detection signal and the position of the probe 101 may be stored in association with each other. In this case, the data array device 106 stores the position of the probe 101 when the binarized reference signal changes based on the speed at which the insertion / extraction machine 102 pulls out the cable 203 in the storage unit. Based on the position of the probe 101 at this time, the data array device 106 shifts the flaw detection data so that signals indicating the reference site are aligned in the flaw detection data of the plurality of tubes.

  In the first to third embodiments, the first flaw detection coil 201a and the second flaw detection coil 201b detect the change in eddy current by the self-induction method, but the change in eddy current by the mutual induction method. It may be detected.

  In the first and second embodiments, the photodetector 202 is disposed on the intersection line between the aforementioned surface S3 and the outer peripheral surface of the probe. The photodetector 202 is probed from a position on this intersection line. They may be shifted in the axial direction. As a result, the flaw detection signal changes greatly at the timing before / after the timing at which the reference signal changes greatly at the tube end. The inspector can double-check that the tube end has been detected by checking the flaw detection signal and the reference signal on the display device 107.

101, 501, 701 ... Probe 102 ... Insertion / extraction machine 103 ... Eddy current flaw detector 104 ... Signal amplifier 105 ... A / D converter 106 ... Data array device 107 ... Display devices 201a, 201b ... Flaw detection coil 202 ... Photo detector 203 ... Cable 204 ... Probe housing 504 ... Photodetector 603 ... Optical fiber 704 ... Optical excitation / detector 805 ... Light source 1000 ... Heat exchanger 1001 ... Heat transfer tube 1002 ... Tube plate 1003 ... Support plate

Claims (8)

An eddy current flaw detection system for detecting defects in a plurality of tubes,
A flaw detection coil for inducing an eddy current in the tube and detecting a change in the induced eddy current; and a probe having a reference portion sensor for outputting a reference signal corresponding to a reference portion representing a portion where the structure of the tube changes. ,
An eddy current flaw detector for flaw detection by applying an excitation voltage to the flaw detection coil;
An insertion / extraction section for inserting the probe into the tube and extracting the inserted probe from the tube;
A data array device that shifts the flaw detection data so as to align signals indicating the reference part in the flaw detection data of the plurality of tubes based on the reference signal output from the reference part sensor;
An eddy current flaw detection system comprising a display device for two-dimensionally displaying flaw detection data of a plurality of shifted tubes. The eddy current flaw detection system according to claim 1,
The data array device includes:
Measuring the position data indicating the position of the probe while the probe is pulled out of the tube by the insertion pulling unit;
While the probe is pulled out from the tube by the insertion / extraction unit, flaw detection is performed from a change in eddy current detected by the flaw detection coil, and flaw detection data and measured position data of the probe are stored in association with each other,
Based on the reference signal output from the reference part sensor, the reference part of the tube is detected,
Storing the probe position data measured when detecting the reference site of the tube;
The flaw detection data is shifted based on the probe position data measured when detecting the reference portion of the tube so that signals indicating the reference portion are aligned in the flaw detection data of the plurality of tubes. Eddy current flaw detection system. The eddy current flaw detection system according to claim 2,
The reference part sensor has a photodetector for detecting light,
The eddy current flaw detection system according to claim 1, wherein the photodetector outputs a reference signal corresponding to a reference portion of the tube based on a change in the detected light amount. The eddy current flaw detection system according to claim 3,
The probe further includes a light source,
The photodetector detects an eddy current flaw based on a change in reflected light of the light irradiated from the light source and reflected from the surface of the tube. system. The eddy current flaw detection system according to claim 4,
The eddy current flaw detection system, wherein the reference part sensor detects an end of the pipe as a reference part of the pipe. The eddy current flaw detection system according to claim 1,
The reference site sensor has an optical fiber, and one end of the optical fiber is disposed on the outer periphery of the probe,
The eddy current flaw detection system further converts an optical signal taken from one end of the optical fiber and output from the other end of the optical fiber into an electrical signal, and outputs the electrical signal as a reference signal to the data array device. An eddy current flaw detection system comprising: The eddy current flaw detection system according to claim 1,
The reference site sensor includes an eddy current flaw sensor that induces an eddy current in the tube and detects a change in the induced eddy current;
The eddy current flaw detection sensor outputs a reference signal corresponding to a reference portion of the tube based on a detected change in eddy current. An eddy current flaw detection method for detecting defects in a plurality of tubes,
A probe having a flaw detection coil for inducing an eddy current in the tube and detecting a change in the induced eddy current, and a reference portion sensor for outputting a reference signal corresponding to a reference portion representing a portion where the structure of the tube changes. An insertion / extraction step of inserting into the tube and extracting the inserted probe from the tube;
Based on the reference signal output from the reference part sensor, a shift step of shifting the flaw detection data so that signals indicating the reference part are aligned in the flaw detection data of the plurality of tubes.
An eddy current flaw detection method comprising a display step of two-dimensionally displaying flaw detection data of a plurality of shifted tubes.

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