JP2007003469A - Tube group inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish an inspection technology that can accurately inspect a tube group constituted by tubes with the same shape such as boiler heat exchanger tubes in a short time, and can inspect thinning and crack occurring in the heat exchanger tubes inexpensively in the short time. <P>SOLUTION: In this tube group inspection device, a plurality of probes 11 for inputting transverse wave of horizontally polarized wave propagating in the direction of the axial center of a heat exchanger tube 1 at an angle of refraction of 90° and receiving the reflected signal are disposed on the outer peripheral surface of the heat exchanger tube 1. An excitation signal generated in an excitation signal generating section 18 is distributed in an excitation signal dispensing section 17 according to the number of the probes 11 and is transmitted to an excitation signal compensating section 16, excitation signal corrected every probe 11 is transmitted from the excitation signal compensating section 16, the intensity of the excitation signal to be transmitted from the excitation signal compensating section 16 to the probes 11 is controlled with reference to the received signal from a sensitivity compensation test body 14, and a received signal processing section 19 for processing a reflected signal from the inspected tube 1 received by the probes 11 is disposed to extract a useful signal from the received signal with reference to the database 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for inspecting a tube group using ultrasonic waves, and in particular, inspects scratches such as corrosion and cracks generated in a heat exchanger tube such as a boiler composed of tubes having the same material and shape. The present invention relates to a tube group inspection apparatus suitable for the above.

  Since the outer surface of a heat exchanger tube such as a boiler is exposed to a flame, scratches such as corrosion and cracks are generated on the outer surface. Moreover, since the steam circulating inside transforms into water at the time of stoppage, scratches such as corrosion and cracks occur on the inner surface, which may lead to leakage accidents, so periodic inspection is indispensable.

  In order to suppress these problems as much as possible, conventionally, an ultrasonic probe attached to the end of the cable is sent to the inside of the heat exchanger tube with pressure water, and inspection of scratches such as corrosion and cracks from the inside of the heat exchanger tube (See Patent Document 1).

  On the other hand, an apparatus that performs a batch inspection of a long distance by transmitting a Lamb wave from the outer surface of the test tube and receiving a reflection signal thereof is also disclosed. For example, in Patent Document 2, the contact state of a plurality of transmitters to a test body is checked, the received signal is corrected based on the check result, and the corrected data is synthesized, thereby combining the single mode. An ultrasonic flaw detector that realizes a state equivalent to transmitting a Lamb wave is disclosed.

Further, in Patent Document 3, two pairs of transmitter / receiver groups composed of four transmitter / receiver groups arranged at equal intervals along the outer periphery of the test tube are provided, one from a total of eight transmitter / receiver groups. Is selected as a transmitter / receiver group for transmission and one or more are selected as a transmitter / receiver group for reception, and a plurality of transmissions are performed by changing a combination of the transmitter / receiver group for transmission, and as a result, This correction is performed by adding the received signals obtained until the lowest-order torsion mode becomes dominant, and obtaining a correction coefficient corresponding to the contact state of each transceiver group from the ratio of the maximum amplitude between the added signals. There is shown an ultrasonic flaw detector that corrects each of the plurality of received signals based on a coefficient and then synthesizes and applies a time shift process to identify the direction of the received signal.
JP-A-63-187152 JP 2003-57212 A JP 2004-347549 A

  In the automatic ultrasonic flaw detection system for a pipe shown in Patent Document 1 described above, an apparatus (for example, a device required for sending an ultrasonic probe attached to the tip of a cable into the heat exchanger pipe with pressure water) , Insertion shaft, insertion shaft moving device, pressure water jet nozzle, wire control device, cable storage device, pressure water supply pump, pressure water flow rate adjustment and flow direction control device, etc.), and over the entire length of the pipe Since it is necessary to inspect while sending the acoustic probe, there is a problem that the inspection takes a long time.

  Further, in the apparatus disclosed in Patent Document 2 described above, the amplitude is determined from the amplitude level of the Lamb wave that is directly propagated from the transceiver group selected for transmission to the transceiver group selected for reception. The reception data equivalent to the reception data when the contact state of the transmitter / receiver group is uniform is obtained by correcting each received data with the Lamb wave transmission / reception efficiency on the contact surface of the transmitter / receiver group. Here, the Lamb wave used for the calculation of the Lamb wave transmission / reception efficiency on the contact surface of the transceiver group is propagated and received in a two-dimensional wave propagation form. There is a problem that the correction error becomes large because it is a Lamb wave propagated and received in a three-dimensional wave propagation form. In addition, each received data is corrected with the Lamb wave transmission / reception efficiency on the contact surface of the transceiver group obtained from the amplitude level of the Lamb wave reflected from the end face of the test tube, and the received data when the contact state of the transceiver group is uniform Although there is no consideration when there is no pipe end in the inspection area, it cannot be applied to the tube group inspection of boiler heat exchanger pipes that do not have a pipe end as described later. There is.

  In addition, a large number of scratches may occur in the test tube. In such a case, the device shown in Patent Document 3 described above may not be able to identify the direction of the received signal from the scratch. This example will be described with reference to FIGS. In addition, since the code | symbol and name used for description are united with patent document 3, it has the same meaning. FIG. 12 shows a part of the ultrasonic flaw detector according to Patent Document 3. Scratches 2a1 and 2a2 are located on the left side of a transceiver group 4A composed of four transceiver groups 4a to 4d, and four transceivers. It is assumed that a flaw 2b1 and a flaw 2b2 are present on the pipe to the right of the transmitter / receiver group 4B composed of the groups 4e to 4h. Here, an interval L3 between the transmitter / receiver group 4A and the transmitter / receiver group 4B, an interval L2 between the transmitter / receiver group 4A and the scratch 2a1, an interval L1 between the scratch 2a1 and the scratch 2a2, an interval L4 between the transmitter / receiver group 4B and the scratch 2b1, and a scratch 2b1 It is assumed that the interval L5 of the scratch 2b2 is equal.

  In the setting as described above, the data AA ′, BB ′, CC ′, and DD ′ that are assumed to be obtained by the process of step 115 shown in FIG. In the data AA ′, the received signals of the scratches 2a2 and 2b1 overlap. In the data BB ′, the received signals of the scratches 2a1 and 2b1 and the scratches 2a2 and 2b2. Since the received signals of 2a2 and 2b2 overlap with each other in the data DD ′, the received signals of 2a1 and 2b2 overlap each other. Therefore, in step 116, time shift processing is performed on the data AA ′, BB ′, CC ′, and DD ′. However, it is difficult to identify the direction of each scratch from overlapping scratch signals.

  As described above, in the conventional technology, since an ultrasonic sensor is inserted into the boiler heat transfer tube to inspect the thinning and cracking generated in the heat transfer tube, a large-scale device is required and enormous cost and time are required. is required.

  Therefore, an object of the present invention is to perform inspection of a tube group composed of tubes of the same shape like a boiler heat transfer tube in a high accuracy and in a short time, and to inspect for thinning and cracks occurring in the heat transfer tube at a low cost and in a short period of time. It is to establish inspection technology that can be used.

The problems of the present invention are solved by the following means.
According to the first aspect of the present invention, one or more probes for receiving a reflected signal by causing a horizontally polarized transverse wave propagating in the axial direction of the test tube to be incident at a refraction angle of 90 degrees are provided on the test tube. Provided on the outer peripheral surface of the same cross section near the end, and covered by the one or more probes on the outer peripheral surface of the same cross section near the end opposite to the probe installation portion of the test tube. A sensitivity compensation test body having a function of reflecting the horizontally polarized wave that has entered the test tube is provided, and an excitation signal generator that generates an excitation signal to be sent to each probe is generated by the excitation signal generator. An excitation signal distributor for distributing the excitation signal according to the number of the probes, an excitation signal compensator for transmitting the excitation signal corrected for each probe, and a received signal from the sensitivity compensation test body The function of controlling the intensity of the excitation signal sent from the excitation signal compensation unit to the probe with reference to FIG. A tube group inspection apparatus having a function of extracting a useful signal from the received signal with reference to a database, and a received signal processing unit for processing a reflected signal from the test tube received by the probe It is.

  According to the second aspect of the present invention, the horizontally polarized transverse waves propagating from one or more probes in the axial direction of the test tube are the same from the equidistant positions on the outer peripheral surface of the same cross section of the test tube. 2. The tube group inspection apparatus according to claim 1, which is incident in phase.

  A third aspect of the present invention is the tube group inspection device according to the first or second aspect, wherein the probe includes a piezoelectric element, and the piezoelectric element has a curvature concentric with the test tube.

  According to a fourth aspect of the present invention, there is provided the tube group inspection apparatus according to any one of the first to third aspects, wherein the database is a received signal from a healthy tube or a dummy tube having the same material and shape as the test tube.

  In the invention according to claim 5, the reception signal processing unit can subtract the reception signal from the healthy tube or the imitation tube of the database from the reception signal from the test tube by designating the entire database or a specific range. 5. The tube group inspection apparatus according to claim 1, which has a function of sending to a display unit.

  According to the sixth aspect of the present invention, the received signal processing unit can perform frequency modulation by designating a specific range of the database, and further allows time shift, and receives the received signal from the healthy tube or the imitation tube of the obtained database. 6. The tube group inspection device according to claim 1, wherein the tube group inspection device has a function of subtracting from a reception signal from the inspection tube and sending the result to a display unit.

  A seventh aspect of the present invention is the tube group inspection apparatus according to any one of the first to sixth aspects, wherein the sensitivity compensation test body is configured to be separable and can be attached to any position of the test tube.

  According to the first aspect of the present invention, horizontally polarized horizontal waves incident at the same phase from a plurality of positions on the outer circumference of the same cross section of the test tube propagate in a long distance, and the reflected signal is transmitted to the test tube. Since it is possible to inspect a long tube at a time by receiving it with one or more probes provided on the outer peripheral surface of the same cross section near the end of the tube, it is possible to inspect without requiring a large-scale device It does not take time. Also, the horizontally polarized transverse wave that is incident from the probe constituting the tube group inspection apparatus into the test tube at a refraction angle of 90 degrees propagates in one direction of the test tube, so that the received signal is transmitted from the probe. There is no need to identify the left or right direction. Further, since the received signal from the sensitivity compensation test body having the same wave propagation form as the received signal is used to correct the intensity of the excitation signal sent to the probe, the correction error does not increase.

  According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, in addition to the effect of the invention according to the first aspect, the horizontally polarized horizontal wave incident at the same phase from the equally spaced positions on the outer circumference of the same cross section of the test tube. Since the reflected signal can be received by one or more probes provided on the outer peripheral surface of the same cross section near the end of the test tube, the long tube can be inspected collectively.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, it is possible to transmit / receive a horizontally polarized transverse wave by the piezoelectric element incorporated in the probe. By adopting a structure having a curvature that is concentric with the test tube, the movement of the horizontally polarized particles of the transverse wave moves along the outer peripheral surface of the test tube, which is horizontal compared to the case of using a plate-like piezoelectric element. The polarized transverse wave can be efficiently transmitted to the test tube.

  According to the invention described in claim 4, in addition to the effect of the invention described in any one of claims 1 to 3, the database uses a received signal from a healthy tube or a dummy tube having the same material and shape as the test tube. Therefore, the tube group inspection can be performed even if the test tube does not have a healthy tube.

  According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the present invention, the useful signal is extracted from the received signal with reference to the database, so that the received signal has a low noise level. Can be obtained.

  According to the invention described in claim 6, in addition to the effects of the invention described in any one of claims 1 to 5, the frequency can be modulated by designating a specific range of the database, and further, a time shift is possible. Since the received signal from the healthy tube or imitation tube in the database can be subtracted from the received signal from the test tube, there is a variation in the positional relationship between the butt weld and fillet weld, for example, and the unnecessary mode Even if there is a received signal, the received signal from the scratch can be extracted.

  According to the seventh aspect of the invention, in addition to the effect of the first aspect of the invention, the sensitivity compensation test body is configured to be separable and attached to an arbitrary position of the test tube. Because it is flexible, it can be inspected even with a test tube without a tube end.

  A tube group inspection apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a tube group inspection apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a detailed configuration of the probe from a direction crossing the tube axis according to the embodiment of the present invention, FIG. 2 (a) is a sectional view in the tube axis direction, and FIG. 2 (b) is a tube. It is a cross-sectional view of the direction which crosses an axis | shaft. FIG. 3 is a view of the sensitivity-compensated test body viewed from the direction crossing the tube axis according to the embodiment of the present invention.

  In FIG. 1, since the heat exchanger tube 1 (outer diameter 60.5 mm, wall thickness 3.9 mm) reaches 20 m in total length, the tube 1 and the tube 1 are joined to each other by a butt weld portion 2 and a bent portion 5 is provided. Yes. The headers 3a and 3b are attached to both ends of the heat exchanger tube 1 by fillet welds 4a and 4b. Further, the heat exchanger tube 1 has scratches 6 (6a, 6b, 6c, 6d) having an outer diameter of 3 mm and a depth of 2 mm.

  Four probes 11 (11a, 11b, 11c, 11d) are mounted on the outer peripheral surface of the same cross section at one end of the heat exchanger tube 1 having such a structure, and the other end of the heat exchanger tube 1 is attached. A sensitivity compensation test body 14 is attached by bolts 15 on the outer peripheral surface of the same cross section. Four probes 11 (11a, 11b, 11c, 11d) are connected in parallel to the excitation signal compensator 16, and the four probes 11 (11a, 11b, 11c, 11d) are connected simultaneously. Can be excited. An excitation signal distributor 17 and an excitation signal generator 18 are connected in series in this order to the excitation signal compensator 16, and signals from the excitation signal generator 18 are probed via the excitation signal distributor 17. The signals are distributed according to the number of children 11 and sent to the excitation signal compensator 16.

  Further, four probes 11 (11a, 11b, 11c, 11d) are connected in parallel to the received signal processing unit 19, and further, the received signal processing unit 19 includes an excitation signal compensating unit 16, a database 20, and a display unit. 21 is also connected.

  The number of probes 11 is not limited to four, and it is desirable to cover the entire circumference of the heat exchanger tube 1 with a large number of probes 11. Therefore, the number may be increased or decreased according to the width of the probe 11 or the outer diameter of the heat exchanger tube 1.

  The reception signal processing unit 19 has a function of controlling the excitation signal compensation unit 16 with reference to the reception signal from the sensitivity compensation test specimen 14, and is useful from the reception signal with reference to the entire database 20 or a specific range. Has a function of extracting a simple signal. Further, the reception signal processing unit 19 has a function of modulating a frequency by designating a specific range of the database 20 and subtracting a reception signal from the heat exchanger tube 1 by adding a time shift.

The excitation signal compensator 16 has a function of correcting the intensity of the excitation signal sent to the probe 11 (11a, 11b, 11c, 11d) under the control of the received signal processor 19.
The display unit 21 displays the processing result in the reception signal processing unit 19 and graphically displays contents such as the presence / absence of the scratch 6, the position of the scratch 6 and the size of the scratch 6.

  FIG. 2 shows a probe 11 (11a, 11b, 11c, 11d) attached to one end of the heat exchanger tube 1 and piezoelectric elements 12a, 12b, 12c, 12d on each probe 11a, 11b, 11c, 11d. Sectional view through the axial center of the heat exchanger tube 1 showing the wedges 13a, 13b, 13c, 13d for attaching (Fig. 2 (a)) and a transverse sectional view of the heat exchanger tube 1 (Fig. 2 (b)) Indicates.

  As shown in FIG. 2, the probes 11 (11a, 11b, 11c, and 11d) are arranged at equal intervals in the circumferential direction on the outer peripheral surface of the same cross section of the heat exchanger tube 1, so that the same phase Thus, a horizontally polarized wave can be incident on the heat exchanger tube 1. In addition, a piezoelectric element 12 (12a, 12b, 12c, 12d) having a curvature R concentric with the heat exchanger tube 1 is attached to the wedge 13 (13a, 13b, 13c, 13d) inside the probe 11. It is in a state.

  The piezoelectric elements 12 (12a, 12b, 12c, 12d) are responsible for electroacoustic conversion and transmit / receive horizontally polarized transverse waves. The wedge 13 gives an incident angle α to the horizontally polarized transverse wave electroacoustic-converted by the piezoelectric element 12 and gives a refraction angle θ to the outgoing angle from the horizontally polarized transverse wave wedge 13. A horizontally polarized transverse wave can be incident only in the right direction of the exchanger tube 1 or only a reflected signal from the right direction can be transmitted to the piezoelectric element. The piezoelectric elements 12a, 12b, 12c, and 12d and the wedges 13a, 13b, 13c, and 13d are formed of arcuate members having the same curvature as that of the outer peripheral surface of the heat exchanger tube 1.

  FIG. 3 shows a cross-sectional direction of the heat exchanger tube 1 and the sensitivity compensation test body 14 attached to the outer periphery thereof. The sensitivity compensation test body 14 has an inner diameter equal to the outer diameter of the heat exchanger tube 1. The cylinder is divided into two parts, and can be attached to any position of the heat exchanger tube 1 by tightening the sensitivity compensation test bodies 14a, 14b divided into two parts with two bolts 15.

Next, the operation of the tube group inspection apparatus having the above configuration will be described with reference to the drawings.
FIG. 4 shows a flow of inspecting the heat exchanger tube 1 of the boiler by the tube group inspection device of this embodiment, and this flow is composed of an excitation signal correction mode and an inspection mode.

  First, the excitation signal correction mode will be described. In step S <b> 1, the excitation signal generator 18 generates a basic excitation signal for exciting the probe 11. As a waveform of the excitation signal, a sine wave, a rectangular wave, a triangular wave, a ramp-up wave, a ramp-down wave, or the like can be generated. However, when importance is attached to the evaluation accuracy of the scratch 6, a sine wave having a narrow band characteristic is generated. Application is desired. The frequency may be determined according to the length of the test tube (heat exchanger tube) 1 to be inspected and the size of the scratch 6 to be detected. The test tube (heat exchanger tube) 1 as shown in FIG. For this, 50 KHz to 200 KHz is applied.

Next, in step S <b> 2, the excitation signal distribution unit 17 distributes the excitation signal sent from the excitation signal generation unit 18 into four systems and sends it to the excitation signal compensation unit 16.
Furthermore, in step S3, the excitation signal compensator 16 transmits the four systems of excitation signals sent from the excitation signal distributor 17 to the probes 11a, 11b, 11c, and 11d.

  In the next step S4, the piezoelectric elements 12a, 12b, 12c, and 12d each vibrate with thickness because the polarization axis and the electric field axis are orthogonal to each other. Signals (electrical signals) are converted into horizontally polarized transverse waves. Further, as shown in FIG. 2 (b), since each piezoelectric element 12a, 12b, 12c, 12d has a curvature R that is concentric with the heat exchanger tube 1, the movement of the horizontally polarized particles is the heat exchange. Since the movement is along the outer peripheral surface of the vessel 1, the plate-like piezoelectric element 12 ′ (12 a ′, 12 b ′, 12 c ′, 12 d ′) shown in FIG. Compared with the heat exchanger tube 1, the heat exchanger tube 1 is effectively transmitted.

Next, in step S5, each wedge 13a, 13b, 13c, 13d gives an incident angle α to the horizontally polarized transverse wave electroacoustic-converted by each piezoelectric element 12a, 12b, 12c, 12d, and the heat exchanger tube 1 Refracts horizontally polarized transverse waves incident on the light according to Snell's law. For example, if a plastic wedge 13 is made of plastic having a sound velocity Cs of 1430 m / s and an incident angle α of 26 degrees is given to the horizontally polarized wave which has been electroacoustic converted, the refraction angle θ = Since it is incident at 90 degrees, the incident horizontally polarized wave is propagated only on the outer surface of the heat exchanger tube 1 in the right direction of FIG. Here, since the horizontally polarized transverse wave propagating through the heat exchanger tube 1 has a refraction angle of 90 degrees, the mode parameter is zero order, and there is an effect of eliminating velocity dispersion due to frequency.
Snell's law is expressed as sin θ = Cgsin α / Cs, and the group velocity Cg at which the horizontal wave of horizontal propagation propagates through the heat exchanger tube 1 is 3262 m / s.

  Next, in step S6, the horizontally polarized waves that have propagated through the heat exchanger tube 1 are flaws 6 (6a, 6b, 6c, 6d), butt welds 2, bends 5, sensitivity compensation specimens 14 and corners. It is reflected by the meat weld 4 b and received by the probe 11.

  Further, in step S7, the reflected signals received by the probes 11a, 11b, 11c, and 11d are respectively transmitted to the corresponding piezoelectric elements 12a, 12b, 12c, and 12d via the wedges 13a, 13b, 13c, and 13d. Then, acoustoelectric conversion is performed by the piezoelectric elements 12a, 12b, 12c, and 12d.

Next, in step S8, the reception signal processing unit 19 selects a reception signal transmitted from the probe 11a among reception signals transmitted from the probes 11a, 11b, 11c, and 11d. Then, a gate is set to the received signal 14 ′ from the sensitivity compensation test body 14 included in the selected received signal, the amplitude is detected, and a control signal is set so that the amplitude becomes a predetermined height. The signal is sent to the excitation signal compensator 16. The gate is a means for extracting a signal generated in a specific time domain. Setting the gate means that the distance from the probe to the sensitivity-compensated specimen and the laterally polarized horizontal wave are substantially known. The time for obtaining the received signal from the sensitivity compensation test specimen is calculated based on the speed of propagation through the heat exchanger tube, and a means for extracting the signal generated in the time domain is set.
FIG. 7 shows a situation in which a gate is set for the received signal 14 ′ from the sensitivity compensation test body 14 included in the received signal sent from the probe 11a.

Next, in step S9, the excitation signal compensator 16 receives the control signal from the reception signal processor 19 and corrects the intensity of the excitation signal sent to the probe 11a.
Next, returning to step S8, the steps of sequentially switching the probes 11b to 11d and correcting the excitation signal are repeated. Finally, it is confirmed that the amplitude of the received signal from the sensitivity compensation test body 14 is a predetermined height for all the probes 11a, 11b, 11c, and 11d, and the excitation signal correction mode is terminated. .

The inspection mode will be described below. Steps 1 to S7 are the same operations as those in the excitation signal correction mode.
In step S10 following step 7, the reception signal processing unit 19 synthesizes the reception signals sent from the four probes 11a, 11b, 11c, and 11d. FIG. 8 shows the synthesized received signal. In the synthesized received signal shown in FIG. 8, the received signal 6a ′ from the scratch 6a, the received signal 6b ′ from the scratch 6b, the received signal 6c ′ from the scratch 6c, and the received signal 6d ′ from the scratch 6d can be confirmed. However, it is difficult to discriminate by the received signals 2 ′, 2 ″ from the butt welded portion 2, the received signal 5 ′ from the bent portion 5, and the received signal 4b ′ from the fillet weld 4b. Here, in the received signal 2 ″ from the butt weld 2, as shown in FIG. 5, the signal reflected by the butt weld 2 travels backward through the path, further reflected by the fillet weld 4 a, and again. It is a reception signal of the signal reflected by the butt welding part 2. FIG. Further, since the reception signal 2 ′ ″ of the unnecessary mode generated at the butt weld 2 and the reception signal 4b ″ of the unnecessary mode generated at the fillet weld 4b are also seen, it is further difficult to identify the scratch signal. Yes.

  Therefore, in the next step S11, the reception signal processing unit 19 uses the synthesized signal obtained in step S10 to obtain the whole or a specified part of the reception signal of the healthy tube 1a stored in the database 20 in advance, and further frequency modulation. The received signals 6a ′, 6b ′, 6c ′ and 6d ′ from the scratches 6a, 6b, 6c and 6d are extracted.

Here, means for obtaining the received signal of the healthy pipe 1a stored in the database 20 will be described with reference to FIG.
As shown in FIG. 9, the tube group of the boiler is composed of several hundred heat exchanger tubes 1 having the same material and shape. It is known from experience that scratches 6 are not generated in the heat exchanger tube 1a located in the center in the furnace width direction and are healthy. Therefore, the operation of Steps S1 to S10 shown in FIG. 4 is performed on the heat exchanger tube (sound tube) 1a located in the center of the furnace width, and the reception signal obtained in Step S10 is the reception signal of the sound tube 1a. Is stored in the database 20. FIG. 10 shows the received signal of the healthy pipe stored in the database 20.
Even when there is no sound pipe 1a, the same effect can be obtained by using the imitation pipe having the same material and shape as the heat exchanger pipe 1 and using the received signal obtained by the operations in steps S1 to S10.

  Next, in step S12, the display unit 21 represents the result of extracting the received signals 6a ', 6b', 6c ', and 6d' from the scratches 6a, 6b, 6c, and 6d, respectively. FIG. 11 shows the result of subtracting the entire received signal of the healthy pipe 1a stored in the database 20 in advance from the combined signal obtained in step S10. In the display shown in FIG. 11, the vertical axis represents the output of the received signal and is related to the size information of the scratch 6. The horizontal axis represents the reception time of the received signal, and is related to the position information of the scratch 6. As can be seen from the results shown in FIG. 11, the received signals 2 ′ and 2 ″ from the butt weld 2 which have become obstacles, the received signal 5 ′ from the bent portion 5, and the received signal 4b from the fillet weld 4b Further, the unnecessary mode received signal 2 ′ ″ generated at the butt weld 2 and the unnecessary mode received signal 4b ″ generated at the fillet weld 4b are canceled out, and scratches 6a, 6b, 6c, 6d The received signals 6a ′, 6b ′, 6c ′ and 6d ′ are extracted. The reception time of the received signals from the scratches 6a, 6b, 6c and 6d is denoted as a scratch position. Further, the outputs of the received signals 6a ', 6b', 6c ', 6d' are substantially equal, and the sizes of the scratches 6a, 6b, 6c, 6d are equal.

Next, an operation of subtracting a part of the reception signal of the healthy tube 1a from the combined signal obtained in step S10 in step S12 will be described.
There may be variations in the positional relationship between the butt weld 2, the bend 5, the sensitivity compensation test piece 14, and the fillet weld 4 b that form the heat exchanger tube 1. In this case, the reception signal regions from the butt weld 2, the bend 5, the sensitivity compensation test specimen 14, and the fillet weld 4 b are specified for each of the reception signals of the healthy pipe 1 a stored in the database 20 in advance. The butt weld 2 that forms the heat exchanger tube 1 by setting the gate for each, shifting the amount of time corresponding to the positional shift to this, and subtracting it from the combined signal obtained in step S10, Even when there is a variation in the positional relationship between the bent portion 5, the sensitivity compensation test specimen 14, and the fillet weld 4b, the received signals 6a ′, 6b ′, 6c ′, and 6d ′ from the scratches 6a, 6b, 6c, and 6d are extracted.

  Next, in step S12, the operation of frequency-modulating a specific part of the received signal of the healthy tube 1a previously stored in the database 20 and subtracting this from the synthesized signal obtained in step S10 will be described.

  An unnecessary mode signal is also generated from the butt weld 2 and fillet weld 4b. Since the signal of the unnecessary mode has a property that the speed of sound changes depending on the frequency, if the positional relationship between the butt weld 2 and the fillet weld 4b forming the heat exchanger tube 1 varies, the composite signal obtained in step S10. From the received signals 6a ', 6b', 6c ', flaws 6a, 6b, 6c, 6d even if the whole received signal of the healthy tube 1a stored in the database 20 in advance or a specified part is subtracted from 6d ′ may not be extracted clearly. In this case, the reception signal areas from the butt weld 2 and fillet weld 4b are specified for each of the composite signals obtained in step S10, the gate is set for each, and the frequency is measured for each. Next, the reception signal areas from the butt weld 2 and fillet weld 4b are identified for each of the reception signals of the healthy pipe 1a stored in the database 20, and a gate is set for each, Frequency modulation is performed so that the frequency is the same as that of the synthesized signal obtained in step S10. Then, by shifting the amount of time corresponding to the positional deviation to this and subtracting it from the combined signal obtained in step S10, the positional relationship between the butt weld 2 and fillet weld 4b forming the heat exchanger tube 1 is obtained. Even when there is variation and signals in the unnecessary mode are received, the received signals 6a ′, 6b ′, 6c ′, and 6d ′ from the scratches 6a, 6b, 6c, and 6d are extracted. However, the signal processing is complicated.

  In the above example, the flaw inspection of the heat exchanger tube 1 of the boiler has been described, but the application of the tube group inspection apparatus of the present invention is not limited by the material and shape of the subject, and the length is several kilometers. Even in the case of sequentially inspecting pipelines that span several tens of meters, it can be widely applied. Furthermore, the function of extracting a scratch signal can also be exhibited.

  Thermal power generation facilities that are shifting to support operation of nuclear power generation have prolonged downtime, and the problem of pitting corrosion occurring in the heat transfer tubes of boilers is becoming apparent, so the present invention will be used continuously in the future. Can be expected. It may also be a particularly advantageous technology for the future when inspection costs are being reduced.

It is a figure which shows the structure of the pipe group test | inspection apparatus concerning the Example of this invention. It is a figure which shows the detailed structure of the probe of the tube group inspection apparatus of FIG. 1, (a) is sectional drawing which passes along the axial center of a heat exchanger pipe | tube, FIG.2 (b) is crossing of a heat exchanger pipe | tube. FIG. It is the figure which looked at the cross-sectional direction of the sensitivity compensation test body of the pipe group inspection apparatus of FIG. 1 attached to the outer periphery of a heat exchanger pipe | tube. It is a figure which shows the flow which inspects the heat exchanger pipe | tube of a boiler with the pipe group test | inspection apparatus of FIG. It is a figure explaining the received signal of the signal reflected twice by the butt welding part at the time of the test | inspection of the heat exchanger pipe | tube of a boiler with the pipe group test | inspection apparatus of FIG. It is a figure explaining the operation | movement when the piezoelectric element which comprises the probe of the other Example of the pipe group test | inspection apparatus of FIG. 1 is flat form. It is a figure which shows the condition which set the gate to the received signal from the sensitivity compensation test body contained in the received signal sent from one probe of the tube group test | inspection apparatus of FIG. It is a figure which shows the synthetic | combination signal obtained in the received signal processing part of the tube group test | inspection apparatus of FIG. It is a figure explaining the means to obtain the received signal of the healthy pipe memorize | stored in the database of the pipe group test | inspection apparatus of FIG. It is a figure which shows the received signal of the healthy pipe | tube memorize | stored in the database of the pipe group test | inspection apparatus of FIG. It is a figure which shows the test result obtained by subtracting the received signal of a healthy pipe | tube from the received signal synthesize | combined in the received signal process of the tube group test | inspection apparatus of FIG. It is explanatory drawing regarding the conventional ultrasonic flaw detector. It is the figure which guessed the concept of the data regarding the conventional ultrasonic flaw detector.

Explanation of symbols

1 Heat Exchanger Tube 1a Healthy Pipe 2 Butt Weld 2 ', 2''Received Signal from Butt Weld 2''' Received Signal 2a1, 2a2, 2b1, 2b2 Scratch 3a, 3b Pipe Generated at Butt Weld 4A, 4B Transceiver group 4a, 4b Fillet weld 4b 'Received signal from fillet weld 4b''Received signal of unnecessary mode generated by fillet weld 5 Curved part 5' Received signal 6a, 6b from curved part , 6c6d scratch
6a ', 6b', 6c'6d 'Received signal from scratch
11a, 11b, 11c, 11d probe
12a, 12b, 12c, 12d Piezoelectric element
12a ′, 12b ′, 12c ′, 12d ′ planar piezoelectric elements
13a, 13b, 13c, 13d wedge
14, 14a, 14b Sensitivity compensation specimen 14 'Received signal from sensitivity compensation specimen
15 Volt 16 Excitation signal compensator
17 Excitation signal distribution unit 18 Excitation signal generation unit
19 Received signal processor 20 Database
21 Display section

Claims (7)

One or more probes for receiving a reflected wave of a horizontally polarized transverse wave propagating in the axial direction of the test tube are incident on the same cross section near the end of the test tube. Horizontally polarized light that is provided on the outer peripheral surface and is incident on the test tube by the one or more probes on the outer peripheral surface of the same cross section near the end opposite to the probe installation portion of the test tube A sensitivity compensation test body having a function of reflecting the transverse wave of
An excitation signal generator for generating an excitation signal to be sent for each probe, an excitation signal distributor for distributing the excitation signal generated by the excitation signal generator according to the number of the probes, and the probe An excitation signal compensator for sending a corrected excitation signal for each of the transducers, and controlling the intensity of the excitation signal sent from the excitation signal compensator to the probe with reference to the received signal from the sensitivity compensation test specimen A reception signal processing unit that has a function and a function of extracting a useful signal from the received signal with reference to a database created in advance, and that processes a reflected signal from the test tube received by the probe; A tube group inspection apparatus characterized by comprising:   Horizontally polarized transverse waves propagating from one or more probes in the axial direction of the test tube are incident at the same phase from equidistant positions on the outer peripheral surface of the same cross section of the test tube. The tube group inspection apparatus according to claim 1.   3. The tube group inspection apparatus according to claim 1, wherein the probe includes a piezoelectric element, and the piezoelectric element has a concentric curvature with the test tube.   4. The tube group inspection apparatus according to claim 1, wherein the database is a received signal from a healthy tube or a dummy tube having the same material and shape as the test tube.   The received signal processing unit has the function of specifying the entire database or a specific range and subtracting the received signal from the healthy tube or the imitation tube of the database from the received signal from the test tube and sending the result to the display unit The tube group inspection apparatus according to claim 1, wherein   The received signal processing unit can specify the specific range of the database and perform frequency modulation, and also allows time shift, and subtracts the received signal from the healthy tube or imitation tube of the obtained database from the received signal from the test tube 6. The tube group inspection apparatus according to claim 1, further comprising a function of sending the result to a display unit.   The tube group inspection apparatus according to any one of claims 1 to 6, wherein the sensitivity compensation test body is configured to be separable and can be attached to an arbitrary position of the test tube.

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