JP5121214B2 - Tube group thinning inspection device and inspection method - Google Patents

Description

  The present invention relates to an apparatus for inspecting a tube group using ultrasonic waves, and is particularly suitable for evaluating a thinning generated in a heat exchanger tube such as a boiler having a narrow interval between tubes. The present invention relates to a tube group thinning inspection apparatus.

  Since heat exchanger tubes such as boilers are exposed to a flame on the outer surface, corrosion thinning occurs on the outer surface. Moreover, since the steam circulating inside transforms into water when it stops, corrosion thinning may occur on the inner surface, leading to a leakage accident, so periodic inspection is indispensable, but the interval between the tubes is narrow. Since it is configured, it is difficult for an inspector to approach and directly perform visual inspection and ultrasonic thickness measurement. Therefore, conventionally, an ultrasonic probe attached to the tip of the cable is sent into the heat exchanger tube with pressure water to measure the thickness 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 reflected signal from the thinned portion 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 shown.

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. Are selected as a transmitter / receiver group for transmission and one or more are selected as a transmitter / receiver group for transmission, and transmission / reception is performed a plurality of times by changing the combination of the transmitter / receiver group for transmission. The received multiple received signals are added until the lowest order torsion mode becomes dominant, and a correction coefficient corresponding to the contact state of each transmitter / receiver group is obtained from the ratio of the maximum amplitude between the added signals. 1 shows an ultrasonic flaw detector that corrects and combines the plurality of received signals based on the above and performs 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 ejection 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 measure the thickness while feeding the acoustic probe, there is a problem that it takes a long time for the inspection.

  Further, in Patent Document 2 described above, it is important to transmit a single-mode Lamb wave to the test body, and the contact state with respect to the test body needs to be the same among a plurality of excitation devices. The specific example is not shown, and as an alternative, the transceiver group obtained from the amplitude level of the Lamb wave directly propagated from the transceiver group selected for transmission to the transceiver group selected for reception is received. There is shown a method of obtaining reception data equivalent to reception data when the contact state of the transmitter / receiver group is uniform by correcting each reception data with the Lamb wave transmission / reception efficiency on the contact surface.

  Here, the Lamb wave used for calculating 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, and each received data corrected for this is received. Has a problem that the correction error increases because it is a Lamb wave propagated and received in a three-dimensional wave propagation form.

  In addition, each received data is corrected by the Lamb wave transmission / reception efficiency at 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 reception when the contact state of the transceiver group is uniform Received data equivalent to the data, but there is no consideration when there is no pipe end in the inspection area, and it cannot be applied to the tube group inspection of boiler heat exchanger tubes that do not have a pipe end as described later. There is a problem to say.

  In addition, many thinnings may occur in the test tube. In such a case, the apparatus shown in Patent Document 3 described above may not be able to identify the direction of the received signal from the thinning. . This example will be described with reference to FIGS. In addition, since the code | symbol and title used for description are united with patent document 3, it has the same meaning. FIG. 8 shows a part of the ultrasonic flaw detector according to Patent Document 3, and a thinning 2a1 and a thinning 2a2 are provided on the left of a transceiver group 4A composed of four transceiver groups 4a to 4d. It is assumed that the thinning 2b1 and the thinning 2b2 are present in the pipe to the right of the transceiver group 4B composed of the transceiver groups 4e to 4h. Here, an interval L3 between the transceiver group 4A and the transceiver group 4B, an interval L2 between the transceiver group 4A and the thinning 2a1, an interval L1 between the thinning 2a1 and the thinning 2a2, and an interval L4 between the transceiver group 4B and the thinning 2b1. The interval L5 between the thinning 2b1 and the thinning 2b2 is assumed to be equal.

  In the above settings, the data AA ′, BB ′, CC ′, DD ′, which are assumed to be obtained by the process of step 115 shown in FIG. 3 of Patent Document 3, are the concept shown in FIG. In the data AA ′, the reception signals of the thinning 2a2 and the thinning 2b1 overlap, in the data BB ′ the reception signals of the thinning 2a1 and the thinning 2b1, and the thinning 2a2 and the thinning 2b2, and in the data CC ′, the thinning 2a1. Since the received signals of the thinning 2b1 and the thinning 2a2 and the thinning 2b2 are overlapped with the reception signals of the thinning 2a1 and the thinning 2b2 in the data DD ′, respectively, the data AA ′, BB ′, CC ′, DD ′ are overlapped in the step 116. However, even if the time shift process is performed, it is difficult to identify the direction of each thinning from the overlapped thinning signals.

  Therefore, an object of the present invention is to provide a tube group thinning inspection apparatus that can inspect heat exchanger pipes in a short time without using a large-scale apparatus and can accurately evaluate the thinning generated in the heat exchanger pipes. And provide inspection methods.

  The problem of the present invention is solved by the following configuration.

  The invention according to claim 1 is an even number for transmitting a horizontally polarized horizontal wave of a specific frequency appropriately selected from a plurality of frequencies propagating in the axial direction of the test tube (1) and receiving the reflected wave. A former probe group composed of a single probe unit (27a to 27d) and a second probe composed of the same number of probe units (28a to 28d) as the number of probes constituting the former probe group. A holder (13) that encloses the group and is attached to the outer surface of the test tube (1), and an even number of probe units (27a to 27d, 28a to 28d) that respectively constitute the pair of probes B and B The acoustic coupling provided between the probe units (27a to 27d, 28a to 28d) and the test tube (1) in order to transmit the horizontally polarized transverse waves transmitted from the test tube (1) to the test tube (1) From the members (33a to 33d, 34a to 34d) and the pair of probes In order to reflect the horizontally polarized transverse wave of the test tube (1) transmitted to each of the test tubes (1), sensitivity compensation test bodies (15a, 15b) provided at both ends of the holder (13), and the test tube ( 1) A vibration absorbing member (17) for selectively absorbing a signal accompanied by an outer surface displacement among transmission / reception signals propagating in the above (1), and each probe constituting the pair of probes A and B by the fluid pressure of the pressurized fluid Crimping means (A) for individually pressing the child units (27a to 27d, 28a to 28d) against the outer surface of the test tube (1), and an even number of probe units constituting the upper probe group (27a to 27d) an excitation signal generator (19) for sending the excitation signal of the specific frequency, and excitation for phase-controlling the excitation signal of the specific frequency sent from the excitation signal generator (19) by 180 degrees Signal phase controller (21) and excitation signal The signal of the specific frequency sent from the phase control unit (21) includes the P / C time (C: the velocity of the transverse wave of the horizontally polarized wave propagating through the test tube (m / sec), P: the pair of probes B An excitation signal delay control unit for giving a delay of the interval (m) between the transducer groups and sending an excitation signal of the frequency to the even number of probe units (28a to 28d) constituting the transducer group (b). 20) and at least one of the sensitivity compensation test bodies (15a, 15b) respectively received by the even number of probe units (27a-27d, 28a-28d) constituting the pair of probes A and B respectively. The function of controlling the pressurized fluid pressure with reference to the reflected signal and transmitting it to the crimping means (A) is added to the signal received by the former probe group and the signal received by the second probe group. Based on the received signal of the frequency obtained in the Tube group thinning having a received signal processing unit (22) having a function represented in the display unit (26) by evaluating the thinning existing in the test tube (1) with reference to the database (25) Inspection equipment.

  According to the second aspect of the present invention, the holder (13) including the pair of probes B and B is configured to be separable and can be attached to any position of the test tube (1). Each probe unit (27a-27d, 28a-28d) constituting the transducer group transmits horizontal waves of horizontal polarization incident simultaneously and in the same phase from the equidistant positions on the outer circumference of the test tube (1). It is a pipe group thinning inspection apparatus of Claim 1 provided with the vibration element (31a-31d, 32a-32d) to perform, respectively.

  According to a third aspect of the present invention, the acoustic coupling members (33a to 33d, 34a to 34d) are tested for all the probe units (27a to 27d, 28a to 28d) that constitute the pair of probes B and B. It is provided on the side in contact with the tube (1), and can be replaced with a material that can be easily adapted according to the surface irregularity state of the test tube (1), and its acoustic impedance value is the probe unit (27a to 27d, 28a). It is a pipe group thinning inspection apparatus of Claim 1 which approximates the acoustic impedance value of the vibration element (31a-31d, 32a-32d) which comprises -28d), and a test tube (1).

  According to a fourth aspect of the present invention, the vibration absorbing member (17) includes an elastic body (35) that is in direct contact with the outer surface of the test tube (1). 2. The tube group thinning inspection apparatus according to claim 1, which can be attached at an arbitrary position.

  According to the fifth aspect of the present invention, the pressure-bonding means (A) includes a pressure fluid generator (24) that generates a pressure fluid, and a fluid that controls the pressure of the pressure fluid by a control signal from the reception signal processor (22). A pressure control unit (23) and cylinders (11a to 11d, 12a to 12d) provided in the holder (13) are provided, and the cylinders (11a to 11d, 12a to 12d) are vibration elements (31a to 31d, 32a). It is a pipe group thinning inspection apparatus of Claim 1 provided with the function of the piston which presses -32d) to the surface of a test tube (1).

According to the sixth aspect of the present invention, the excitation signal delay control unit (20) propagates the P / C time (C: test tube (1)) to the excitation signal sent from the excitation signal phase control unit (21). Probe units (28a to 28d) constituting the probe group by giving a delay of the horizontal wave velocity (m / sec) of the horizontally polarized wave, P: the interval (m) between the pair of probe pairs. the feed, the reception signal processing unit (22), probe unit constituting the signal and Party B probe group that has been received by the probe unit constituting Kinoesagu probe group (27a-27d) (28a to 28d 2. The tube group thinning inspection apparatus according to claim 1, which has a function of adding the signal received in step 1) as a signal shifted in time by P / C time .

  According to the seventh aspect of the present invention, the database (25) includes the ratio of the thinning diameter and the depth with the amplitude ratio of the received signal at the specific frequency as a parameter, and the amplitude and the thinning position of the received signal at the specific frequency. The tube group thinning inspection apparatus according to claim 1, further comprising data indicating a correlation of a defect rate as a parameter.

According to the eighth aspect of the present invention , the transmission signal from the probe unit (27a to 27d) of the upper probe group of the tube group thinning inspection apparatus according to the first aspect is used as the thinning position of the test tube (1). Is reflected by the probe unit (27a to 27d) of the upper probe group, and a transmission signal from the probe unit (27a to 27d) of the upper probe group is detected by the probe unit group. P / C time in the transducer unit (28a to 28d) (C: velocity of the transverse wave of the horizontally polarized wave propagating through the test tube (m / sec), P: distance between the probe group of the pair A and B (m)) The probe unit of the Otsu probe group is reflected on the signal reflected from the thinning position of the test tube (1) received by the probe unit (27a to 27d) of the instep probe group. order mode from the thinning position the signal received at (28a to 28d) by adding a signal obtained by only a time shift P / C time The amplitude of the wave is set to 1 or less, the amplitude of the received signal of the lowest-order torsional mode wave is doubled, and the thickness reduction of the test tube (1) is performed with reference to the database (25) prepared in advance for thickness reduction evaluation This is a tube group thinning inspection method characterized by

According to the ninth aspect of the present invention, the specific propagating in the axial direction of the test tube (1) from the even number of probe units (27a to 27d, 28a to 28d) respectively constituting the pair of probes B and B. Each of the horizontal waves of the horizontally polarized wave having the above frequency is transmitted, and the reflected waves from the sensitivity compensation test body (15b) on the side of referring to the reflected signal are received by the probe units (27a to 27d, 28a to 28d), The probe unit (27a to 27d) is corrected by sequentially correcting the pressing fluid pressure of the probe units (27a to 27d, 28a to 28d) in the direction of the test tube (1) with reference to the reflected wave (A). 27d, characterized in that it is generated by 28a to 28d), by controlling the transmission efficiency of the transmission signal to be transmitted to the test tube (1), to each other uniform intensity of transmission signals propagating through the test tube (1) tube bundle thinning inspection method der according to claim 8, .

According to the first, sixth, and eighth aspects of the present invention, the tube group thinning inspection apparatus according to the present invention can shorten the thinning inspection of the test tube 1 such as a heat exchanger tube without using a large-scale apparatus. I can do it in time. Also Tsu name to the thinning that occurs test tube 1 can be evaluated with high accuracy. In addition, among the horizontally polarized waves transmitted from the former probe group, the signals traveling in the direction of the second probe group are phase-controlled and transmitted from the second probe group that is transmitted with a P / C time delay. Interference with the transmitted signal cancels out, and the horizontally polarized waves transmitted from the Instep probe group propagate only in the direction of the anti-B probe group (direction opposite to 180 degrees), so the received signal is probed. It is not necessary to identify the left and right directions of the child units 27a to 27d and 28a to 28d. Therefore, it is not necessary to perform an easy process of identifying the noise from the left direction and performing noise processing, and the inspection accuracy of the thinning of the test tube 1 is improved. Further, since the received signals from the sensitivity compensation test bodies 15a and 15b attached to arbitrary positions of the test tube 1 can be obtained, the thinning inspection can be performed even on the test tube 1 having no tube end.

According to the second aspect of the present invention, the separable holder 13 can be attached to any position of the test tube 1, so that it can be attached to the test tube 1 from the outside of the tube, and the installation time is shortened. It is possible to cut the tube. (If it is not divided, the tube is cut and one side is separated and inserted into the tube.) In addition, the former probe group and the second probe group respectively provided in each divided holder 13 mounted position of the subject pipe 1 of Ru freely der attached to any position of the test tube 1.

  According to the third aspect of the present invention, the acoustic coupling members 33a to 33d and 34a to 34d are covered on the front surface of all the probe units 27a to 27d and 28a to 28d constituting the pair of probes A and B. Since the test tube 1 is provided on the outer surface side and can be exchanged with a material that is easily adapted to the surface unevenness of the test tube 1, the test tubes of the probe units 27a to 27d and 28a to 28d 1 can be made the same between all the probe units 27a to 27d and 28a to 28d, and the acoustic impedance values of the acoustic coupling members 33a to 33d and 34a to 34d are the probe units 27a to 27d. 28a to 28d, the transducer units 27a to 27d are approximated to the acoustic impedance values of the vibrating elements 31a to 31d, 32a to 32d and the test tube 1. The electromechanical converted shear horizontal polarization is transmitted from 28a~28d efficiently transferred to the test tube 1.

  According to the fourth aspect of the present invention, the vibration absorbing member 17 can be attached to an arbitrary position of the test tube 1 because the vibration absorbing member 17 can be divided. Further, the elastic body 35 provided in the vibration absorbing member 17 absorbs and attenuates higher-order mode signals propagating through the test tube 1 while accompanying the outer surface displacement of the test tube 1, and also involves the outer surface displacement of the test tube 1. Therefore, since the lowest-order torsional mode signal propagating through the test tube 1 is allowed to pass through almost without attenuation, there is an effect of improving the SN ratio of the received signal as compared with the conventional technique.

  Further, the signals received by the probe units 27a to 27d constituting the upper probe group by shifting the signals received by the probe units 28a to 28d constituting the second probe group by P / C time. The function of the received signal processing unit to add can cancel the received signals in the higher order mode (other than the lowest torsional mode), so that the test result with a high S / N ratio can be displayed on the display unit.

According to the inventions of claims 5 and 9 , fluid pressure (vibration elements 31a to 31d, 32a) pressing the probe units 27a to 27d and 28a to 28d against the outer surface of the test tube 1 by the crimping means A The intensity of the reflected signal from the sensitivity compensation test bodies 15a and 15b becomes the same by controlling the intensity of pressing to the outer surface of the test tube 1 of -32d, so that each of the probe units 27a-27d, 28a-28d It is possible to transmit a horizontally polarized transverse wave transmitted from 1 to the test tube 1 with uniform intensity.

  According to the seventh aspect of the present invention, the database 25 sets the ratio of the thinning diameter and the depth using the amplitude ratio of the received signal at a specific frequency as a parameter, and the amplitude and the thinning position of the received signal at a specific frequency as parameters. The reception signal processing unit 22 is obtained by exciting the probe units 27a to 27d and the probe units 28a to 28d at specific frequencies of 40 KHz and 120 KHz, for example. The thinning evaluation of the test tube 1 can be performed with reference to the database 25 based on the received signal.

  A tube group thinning 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 thinning inspection apparatus according to an embodiment of the present invention. 2 is a diagram showing a detailed configuration of the probe group of the tube group thinning inspection apparatus of FIG. 1, FIG. 2 (a) is a sectional view of the former probe group, and FIG. It is sectional drawing of a probe group. 3 is a cross-sectional view showing the configuration of the vibration absorbing member 17 of the tube group thinning inspection apparatus of FIG.

  In FIG. 1, the heat exchanger tube 1 having an outer diameter of 60.5 mm and a wall thickness of 3.9 mm has a total length of 20 m, and therefore, short tubes are joined together by butt welding 2 and have a bent portion 5. The headers 3a and 3b are attached to both ends of the heat exchanger tube 1 by fillet welds 4a and 4b. Further, a thinning 6 exists in the heat exchanger tube 1.

  On the outer surface of the heat exchanger tube 1 having such a structure, a group of upper probes composed of four probe units 27a, 27b, 27c, 27d and four probe units 28a, 28b, 28c, 28d. A band-shaped holder 13 that is divided into two and includes a group of OT probes configured as described above is wound around the outer periphery of the heat exchanger tube 1, and the end of the holder 13 is attached at an arbitrary position by four bolts 14. ing.

  Cylinders 11a to 11d and 12a to 12d are provided in the probe units 27a to 27d and 28a to 28d in the holder 13, respectively. The cylinders 11a to 11d and 12a to 12d function as pistons that press the vibration elements 31a to 31d and 32a to 32d incorporated in the probe units 27a to 27d and 28a to 28d to the outer surface of the test tube 1, respectively. It has.

  And the sensitivity compensation test body 15a and the sensitivity compensation test body 15b divided into two are attached to the outer surface of the heat exchanger tube 1 on both sides of the attachment portion of the holder 13 by four bolts 16a and 16b, respectively.

  Further, the vibration absorbing member 17 is attached to the outer surface of the heat exchanger tube 1 by four bolts 18, and an elastic rubber 35 provided at a position in contact with the outer surface of the heat exchanger tube 1 inside the vibration absorbing member 17. Absorbs and attenuates higher-order mode signals propagating through the heat exchanger tube 1 with the outer surface displacement of the heat exchanger tube 1, and propagates through the heat exchanger tube 1 without the outer surface displacement of the heat exchanger tube 1. The lowest-order torsional mode signal to be transmitted is effectively passed without attenuation. The elastic rubber 35 is preferably obtained from a gel material made mainly of silicone.

  Since the four probe units 27a to 27d constituting the upper probe group are connected directly and in parallel to the excitation signal generator 19, the four probe units 27a to 27d are simultaneously and in phase. Can be excited. On the other hand, the four probe units 28a to 28d constituting the second probe group are connected in parallel to each other, and an excitation signal generator is provided via the excitation signal delay controller 20 and the excitation signal phase controller 21. 19 is connected. The excitation signal delay control unit 20 and the excitation signal phase control unit 21 apply phase control and delay control to the four probe units 28a to 28d of the second probe group, and excite them simultaneously and in the same phase. be able to. In addition, if what reverse polarity is employ | adopted for the probe units 28a-28d which comprise the Otsu probe group, even if the excitation signal phase control part 21 is abbreviate | omitted, the same effect will be acquired.

  The received signal processing unit 22 receives the reflected signal from the sensitivity compensation test body 15b individually received by each of the probe units 27a to 27d constituting the upper probe group and the probe constituting the second probe group. Each of the units 28 a to 28 d receives the reflection signal from the sensitivity compensation test body 15 b received individually, and sends a signal for controlling the air pressure generated by the pressurized fluid generator 24 to the fluid pressure controller 23.

  The fluid pressure control unit 23 controls the air pressure from the pressurized fluid generating unit 24 according to the control signal for each of the probe units 27a to 27d and 28a to 28d received from the reception signal processing unit 22, and the probe units 27a to 27d. The probe units 27a to 27d and the probe unit 28a are sent to the cylinders 12a, 12b, 12c and 12d contained in the cylinders 11a, 11b, 11c and 11d and the probe units 28a to 28d contained in the cylinder 27a. The crimping force on the heat exchanger tube 1 of ~ 28d can be independently controlled.

Further, the reception signal processing unit 22 receives the signals received by the probe units 27a to 27d constituting the upper probe group and the probe units 28a to 28d constituting the second probe group. Can be added to the signal. In addition, the reception signal processing unit 22 receives the probe units 27a to 27d and the probe units 28a to 28d by exciting them at frequencies of 40 KHz and 120 KHz, which are conventionally used for tube group thinning inspection. It has a function of performing the thinning evaluation with reference to the database 25 based on the signal.

  The display unit 26 displays the processing result in the reception signal processing unit 22, whether or not the heat exchanger tube 1 is thinned, the position of the thinning, the ratio of the thinning diameter and depth, and the cross-sectional thinning rate. Is displayed.

  The numbers of the probe units 27a to 27d and the probe units 28a to 28d are not limited to four, and the probe units 27a to 27d and the probe units 28a to 28d are respectively heat exchangers. It is desirable to cover the entire circumference of the tube 1. Therefore, the number may be increased or decreased according to the width of the probe units 27a to 27d and the probe units 28a to 28d and the outer diameter of the heat exchanger tube 1. Further, the excitation frequency is not limited to two types of 40 KHz and 120 KHz, but preferably a low frequency and a high frequency having a ratio of 2 to 5 times the low frequency.

Next, referring to FIG. 2, the configurations of the former probe group and the second probe group will be described in detail.
The holder 13 is provided with cylinders 11a to 11d in the probe units 27a to 27d, and the vibration elements 31a to 31d are accommodated therein. The cylinders 12a to 12d and the vibration elements 32a to 32d are accommodated in the probe units 28a to 28d.

  Air flows from the outside into the space shown in FIG. 2 (in the case of air pressure), and the pressing force in the direction of the outer surface of each of the cylinders 11a to 11d and 12a to 12d is individually adjusted. Vibrating elements 31a to 31d and 32a to 32d are embedded in the tips of the cylinders 11a to 11d and 12a to 12d, respectively, and between the vibrating elements 31a to 31d and 32a to 32d and the outer surface of the test tube 1 will be described later. Foil-like (about 0.2 mm thick) acoustic coupling members 33a to 33d and 34a to 34d are placed. The roles of the acoustic coupling members 33a to 33d and 34a to 34d are to improve the familiarity of the plate-like vibrating elements 31a to 31d and 32a to 32d with the outer surface of the tube 1 and bring them into surface contact somewhat. It is for going.

  The outer circumferences of the cylinders 11a to 11d are provided with sealing materials 29a, 29b, 29c and 29d, and the outer circumferences of the cylinders 12a to 12d are provided with sealing materials 30a, 30b, 30c and 30d. The sealing materials 29a to 29d and 30a to 30d are respectively covered with compressed air sent from the fluid pressure control unit 23 between the cylinders 11a to 11d and 12a to 12d in the probe units 27a to 27d and 28a to 28d and the casing. Leakage toward the test tube surface is prevented.

  Therefore, the cylinders 11a to 11d and 12a to 12d have a piston function. Further, the front surfaces of the cylinders 11a to 11d (surfaces in contact with the heat exchanger tube 1) have acoustic impedance values that approximate the acoustic impedance value of the heat exchanger tube 1 and the acoustic impedance values of the vibration elements 31a, 31b, 31c, and 31d. The ductile silver alloy acoustic coupling members 33a to 33d are detachably attached to the front surfaces of the cylinders 12a to 12d and the acoustic impedance value of the heat exchanger tube 1 and the vibration elements 32a and 32b. Acoustic coupling members 34a to 34d made of silver alloy having acoustic impedance values approximate to the acoustic impedance values of 32c and 32d and having ductility are detachably attached. Therefore, the horizontally polarized transverse waves transmitted from the probe units 27 a to 27 d and 28 a to 28 d can be efficiently transmitted to the heat exchanger tube 1.

  The acoustic coupling members 33a to 33d and 34a to 34d are not limited to silver alloys, and the acoustic impedance values are similar to those of the vibration elements 31a to 31d, 32a to 32d and the heat exchanger tube 1, and the vibration element 31a. In order to stabilize the transmission of waves transmitted to the heat exchanger tube 1 from ˜31d and 32a to 32d, a material having ductility that is suitable for the surface irregularities of the heat exchanger tube 1 is suitable (intermittent in line contact) For example, zinc, tin, copper, lead may be employed.

Next, with reference to FIG. 4, the structure of the database 25 used for the thinning evaluation of the heat exchanger pipe | tube 1 is demonstrated.
The thinning 6 of the heat exchanger tube 1 is generally evaluated by the cross-sectional defect rate (cross-sectional defect rate = thinning cross-sectional area / cross-sectional area of the heat exchanger tube healthy part) based on the amplitude level of the received signal Even if the defect rate is the same, it is difficult to judge whether the detected thinning 6 is shallow and has a large diameter or a deep and small diameter. However, since there is a correlation between the reflectance at the thinning 6 and the excitation frequency, the thinning evaluation is performed with reference to the database 25 using these as parameters.

  FIG. 4A shows a reception signal amplitude ratio (the amplitude of the reception signal obtained when the vibration elements 31a to 31d and 32a to 32d are excited at a frequency of 40 KHz and the vibration elements 31a to 31d and 32a to 32d at a frequency of 120 KHz. The database 25 representing the ratio of the amplitude of the received signal obtained when excited) and the ratio of the thinned diameter to the depth, FIGS. 4B and 4C are the vibration elements 31a to 31d at the frequencies of 120 KHz and 40 KHz. , 32a to 32d, a database 25 for obtaining a defect rate from the relationship between the received signal amplitude and the thinning position.

Next, the operation of the inspection apparatus for the tube group of the heat exchanger tube 1 having the above-described configuration will be described with reference to the drawing, divided into a probe unit (vibration element) pressure bonding force correction flow and a thinning inspection flow.
FIG. 5 shows a probe unit (vibration element) pressure-bonding force correction flow by the tube group inspection apparatus of the present invention.
In step S1, the excitation signal generator 19 generates an excitation signal that is a basis for exciting the probe units 27a to 27d and 28a to 28d. As a waveform of the excitation signal, a pulse wave such as a sine wave, a rectangular wave, a triangular wave, a ramp-up wave, and a ramp-down wave can be generated, but is narrow when importance is attached to the evaluation accuracy of the thinning 6 of the heat exchanger tube 1. Application of a sine wave having band characteristics is desired. The frequency may be determined according to the length of the heat exchanger tube 1 to be inspected or the size of the thinning to be detected. For the thinning inspection of the heat exchanger tube 1 as shown in FIG. Two types of frequencies are selected in the range of 200 KHz, but in the crimping force correction of the probe units 27a to 27d and 28a to 28d, one of these types of excitation signals constitutes the instep probe group. To the probe units 27 a to 27 d and the excitation signal phase controller 21.

  Next, in step S2, since the vibration elements 31a to 31d incorporated in the probe units 27a to 27d constituting the upper probe group have the polarization axis and the electric field axis orthogonal to each other, the vibration operation of thickness sliding is performed. Therefore, the excitation signal (electric signal) sent from the excitation signal generator 19 is converted into a horizontally polarized horizontal wave.

  Next, in step S <b> 3, the vibration elements 31 a to 31 d have materials whose acoustic impedance values approximate to the acoustic impedance values of the probe units 27 a to 27 d and the heat exchanger tube 1, and are easily compatible with the unevenness of the heat exchanger tube 1. Since the acoustic coupling members 33a, 33b, 33c, and 33d are in contact with the heat exchanger tube 1, the horizontally polarized transverse waves that are electromechanically converted by the vibration elements 31a to 31d are efficiently converted into heat exchangers. There is an effect of being incident on the tube 1.

  Next, in step S4, the horizontally polarized transverse wave propagated through the heat exchanger tube 1 is reflected by the sensitivity compensation test body 15b, the butt weld 2, the bent portion 5, the thinning 6, and the fillet weld 4b, and the probe unit. 27a-27d. Note that the position and waveform of the signal in the direction of the sensitivity compensation test specimen 15a are known in advance, and can be deleted by subsequent signal processing (omitted in the description of this step).

  Next, in step S5, the reflected signals received by the probe units 27a to 27d are transmitted to the vibration elements 31a to 31d via the acoustic coupling members 33a to 33d and are subjected to acoustoelectric conversion. In step S6, the reception signal processing unit 22 selects a reception signal transmitted from the probe unit 27a among reception signals transmitted from the probe units 27a to 27d. Then, a gate is set to the reflected signal from the sensitivity compensation test body 15b from the selected received signal, the amplitude is detected, and a control signal is set so that the amplitude becomes a predetermined height. Send to 23.

  The gate is a means for extracting a signal generated in a specific time region. Setting the gate means that the sensitivity compensation test body 15a or the probe unit 27a to 27d or 28a to 28d, which is substantially known, is used. Based on the distance up to 15b and the speed at which the horizontally polarized transverse wave propagates through the heat exchanger tube 1, the time required to obtain the received signal from the sensitivity compensation test body 15a or 15b is calculated, and the signal generated in that time domain It is to set the means to take out.

  Next, in step S7, the fluid pressure control unit 23 receives the control signal from the reception signal processing unit 22, and corrects the pressure of the air sent to the cylinder 11a of the probe unit 27a. Thereafter, the process returns to step S6, and the probe units 27b to 27d are sequentially switched, and the step of sequentially correcting the air pressure sent to the cylinders 11b, 11c, and 11d is repeated.

Finally, it is confirmed that the amplitude of the received signal from the sensitivity compensation test body 15b has a height determined in advance by the probe units 27a to 27d constituting the upper probe group. The crimping force correction step of the probe units 27a to 27d constituting the child group is finished.
Note that the reflection signal from the sensitivity compensation test body 15a need not be considered in this embodiment because the transmission signal only needs to consider the signal in the right direction of the tube 1.

  In this way, the transmission efficiency of the transmission signal generated by the probe units 27a to 27d and transmitted to the heat exchanger tube 1 is controlled, so that the intensity of the transmission signal propagated to the heat exchanger tube 1 is made uniform.

  Next, the crimping force correction step of the probe units 28a to 28d constituting the second probe group will be described. In step S <b> 8, the excitation signal phase controller 21 inverts the excitation signal from the excitation signal generator 19 by 180 degrees and sends it to the excitation signal delay controller 20. Next, in step S9, a P / C time delay is given to the phase-controlled excitation signal, and the signal is sent to the probe units 28a to 28d constituting the second probe group. Here, C is the velocity (m / sec) of the transverse wave of the horizontally polarized wave propagating through the test tube, and P is the distance (m) between the pair of probes B and B.

  Next, in step S10, since the vibration elements 32a to 32d incorporated in the probe units 28a to 28d constituting the second probe group have a polarization axis and an electric field axis orthogonal to each other, the vibration operation of the thickness shear is performed. Therefore, the excitation signal (electric signal) sent from the excitation signal delay control unit 20 is converted into a horizontally polarized wave.

  In step S11, the vibration elements 32a to 32d are made of a material whose acoustic impedance value approximates the acoustic impedance values of the probe units 28a to 28d and the heat exchanger tube 1 and is easily adapted to the unevenness of the heat exchanger tube 1. Since it is in contact with the heat exchanger tube 1 through the acoustic coupling members 34a, 34b, 34c and 34d, the horizontally polarized transverse waves electromechanically converted by the vibration elements 32a to 32d are efficiently incident on the heat exchanger tube 1. There is an effect to make.

  Next, before the description of step 12 and subsequent steps, signals transmitted from the comb-type probe units 27a to 27d constituting the upper probe group with reference to FIG. 7 and propagated in the left direction of the heat exchanger tube 1 Will be canceled by the transmission signals from the probe units 28a to 28d constituting the second probe group, and the effect of propagating only in the right direction will be described.

  FIG. 7 (a) shows that the transmitted signals transmitted from the probe units 27a to 27d constituting the upper probe group propagate through the heat exchanger tube 1 to reduce the thickness 6 (probe units 27a to 27d). And is received by the probe units 27a to 27d of the upper probe group. Further, in the probe units 28a to 28d of the B probe group, the P / C time (C: the velocity of the transverse wave of the horizontal polarization propagating through the heat exchanger tube 1 (m / sec), P: the probe of the pair A and B. Received after a delay of child group interval (m)).

At this time, the transmission signal from the second probe group is incident on the heat exchanger tube 1 from the first probe group because a phase and a delay are given to the transmission signal from the first probe group. Among the transmission signals, the transmission signal propagating in the left direction in the figure is canceled by the transmission signal from the second probe group. Accordingly, since the transmission signal propagates only in the right direction in the drawing in the heat exchanger tube 1, it is not necessary to identify the directionality of the signals received by the probe units 27a to 27d of the upper probe group.

  Further, the transmitted signals excited from the probe units 27a to 27d and 28a to 28d constituting the pair of probes A and B have an effect of improving SN by using dispersion characteristics. In other words, infinite mode waves are mixed in the transmitted / received signal, but the lowest order torsional mode wave has no dispersibility, and all the other higher order modes that impede the evaluation of the thinning position have dispersibility. Can be used to improve the signal-to-noise ratio.

In FIG. 7B, basically, transmission signals from the probe units 27a to 27d of the instep probe group are reflected by the thinning 6, and (A / C) + (A / C) = 2. After (A / C) time, it is received by the probe units 27a to 27d of the former probe group, and (A / C) + (A / C) + is received by the probe units 28a to 28d of the second probe group. Received after (P / C) time.
Here, C is the speed of sound of a transmission / reception signal propagating through the heat exchanger tube 1.

Here, the reception signal of the reflected wave from the thinning 6 in consideration of the sound speed of various mode waves will be described.
C1 is the speed of sound of the lowest order torsional mode wave, C2 is the speed of sound of the higher order mode wave faster than the lowest order torsional mode wave, and C3 is the speed of sound of the higher order mode wave slower than the lowest order torsional mode wave.
The reflected signal from the thinning 6 received by the probe units 27a to 27d of the instep probe group is received after 2 (A / C1) hours in the case of the lowest order torsional mode wave, and is faster than the lowest order torsional mode wave. The higher-order mode wave is received after 2 (A / C2) time, and the higher-order mode wave later than the lowest-order torsional mode wave is received after 2 (A / C3) time.

  In addition, the reflected signal from the thinning 6 received by the probe units 28a to 28d of the second probe group is received after 2 (A / C1) + (P / C1) time in the case of the lowest order torsional mode wave. 2 (A / C2) + (P / C2) time after a higher order mode wave faster than the lowest order torsional mode wave, and 2 (A / C3) after a higher order mode wave slower than the lowest order torsional mode wave ) + (P / C3) time, respectively. Therefore, the relationships Δt2 ′ <Δt2 ″ and Δt3 ′ <Δt3 ”are established.

Where Δt2 ′ = 2 (A / C1) −2 (A / C2)
Δt2 ″ = 2 (A / C1) + (P / C1) − {2 (A / C2) + (P / C2)}
Δt3 ′ = 2 (A / C3) −2 (A / C1)
Δt3 ″ = 2 (A / C3) + (P / C3) − {2 (A / C1) + (P / C1)}
Δt2 ″ = 2 (A / C1) + (P / C1) − {2 (A / C2) + (P / C2)}

For this reason, the signals received by the probe units 28a to 28d constituting the second probe group are added to the signals received by the probe units 27a to 27d constituting the former probe group for (P / C1) time. If the time shift is added, the amplitude of the received signal of the lowest-order torsional mode wave from the thinning 6 is doubled, and the amplitudes of the other higher-order mode waves are reduced to less than 1 times, so the SN ratio is improved. realizable.

Returning to FIG. 5, step 12 and subsequent steps will be described.
In step S12, the horizontally polarized wave that has propagated through the heat exchanger tube 1 is reflected by the sensitivity compensation test body 15b, the butt weld 2, the bent portion 5, the thinning 6, and the fillet weld 4b, and the probe units 28a to 28d. Received at. Here, by confirming that the reflected signal from the sensitivity compensation test body 15a is not received, the transmission signals of the probe units 27a to 27d constituting the upper probe group are left on the paper surface of FIG. It can be confirmed that it does not propagate in the direction.

  In step S13, the reflected signals received by the probe units 28a to 28d are transmitted to the vibration elements 32a to 32d via the acoustic coupling members 34a to 34d and subjected to acoustoelectric conversion.

  Next, in step S14, the reception signal processing unit 22 selects a reception signal transmitted from the probe unit 28a among the reception signals transmitted from the probe units 28a to 28d. Then, a gate is set to the reflected signal from the sensitivity compensation test body 15b from the selected received signal, the amplitude is detected, and a control signal is set so that the amplitude becomes a predetermined height. Send to 23.

  Next, in step S15, the fluid pressure control unit 23 receives the control signal from the reception signal processing unit 22, and corrects the pressure of the air sent to the cylinder 12a of the probe unit 28a. Thereafter, the process returns to step S14, and the probe units 28b to 28d are sequentially switched, and the step of correcting the air pressure sent to the cylinders 12b to 12d is repeated.

  Finally, it is confirmed that the amplitude of the received signal from the sensitivity compensation test body 15b is a height determined in advance by the probe units 28a to 28d constituting the second probe group. Since the crimping force correction step of the probe units 28a to 28d constituting the group is completed, and the crimping force correction to the tube 1 of the vibrating elements 31a to 31d and 32a to 32d is completed in step S16, the sensitivity compensation test specimen 15a and 15b are removed from the tube 1.

  In this way, by controlling the air pressure pressing the probe units 27a to 27d and 28a to 28d, transmission of transmission signals generated by the probe units 27a to 27d and 28a to 28d and transmitted to the heat exchanger tube 1 is performed. The efficiency is controlled to make the intensity of the transmission signal propagating to the heat exchanger tube 1 uniform.

Hereinafter, the thinning inspection flow will be described with reference to FIG.
The thinning inspection was obtained by exciting the probe units 27a to 27d constituting the upper probe group and the probe units 28a to 28d constituting the second probe group with excitation signals of two kinds of frequencies. The thinning evaluation is performed from the received signal.

  First, at step S101, an excitation signal of 120 KHz is generated by the excitation signal generator 19 and sent to the probe units 27a to 27d and the excitation signal phase controller 21 constituting the upper probe group.

Steps S2 to S5 and Steps S8 to S13 are the same operation as the probe unit pressing force correction flow.
Next, in step S102, the reception signal processing unit 22 adds and synthesizes signals received by the probe units 27a to 27d constituting the upper probe group. In step S103, the reception signal processing unit 22 adds and synthesizes signals received by the probe units 28a to 28d constituting the second probe group.

Next, in step S104, adding P / C at better shift to the sum in the reception signal processing unit 22 the combined reception signal. Here, C is the velocity (m / sec) of the transverse wave of the horizontally polarized wave propagating through the test tube, and P is the distance (m) between the pair of probes B and B.

  In step S105, the reception signal processing unit 22 adds and sums the signal obtained in step 102 and the signal obtained in step S104, whereby a useful lowest-order torsional mode signal having no frequency dispersion is interfered and amplified. In addition, an unnecessary high-order mode signal (a signal other than the lowest-order torsional mode signal) having a frequency dispersibility interferes and attenuates, so that an effect of improving the S / N ratio occurs.

Next, in step S201, the excitation signal generator 19 generates an excitation signal of 40 KHz, which is sent to the probe units 27a to 27d and the excitation signal phase controller 21 that constitute the upper probe group.
Steps S2 to S5 and Steps S8 to S13 are the same operation as the probe unit pressing force correction flow.

Next, in step S202, the reception signal processing unit 22 adds and synthesizes signals received by the probe units 27a to 27d constituting the upper probe group.
Further, in step S203, the reception signal processing unit 22 adds and synthesizes signals received by the probe units 28a to 28d constituting the second probe group.

Further, in step S204, the reception signal processing unit 22 adds the P / C at better shift in the received signal added synthesized. Here, C is the velocity (m / sec) of the transverse wave of the horizontally polarized wave propagating through the test tube, and P is the distance (m) between the pair of probes B and B.

  Next, in step S205, the received signal processing unit 22 adds and sums the signal obtained in step 202 and the signal obtained in step S204 to obtain a useful lowest order torsional mode signal having no frequency dispersion. Interference / amplification and useless high-order mode signals (signals other than the lowest-order torsional mode signal) having frequency-related dispersibility interfere and attenuate, resulting in an effect of improving the S / N ratio.

  In step S301, the received signal processing unit 22 refers to the database 25 and evaluates the position, diameter, depth, and loss rate of the thinning 6 existing in the heat exchanger tube from the signals obtained in steps S105 and S205. To do. In step S302, the display unit 26 displays the evaluation result using information from the reception signal processing unit 22.

  In the above example, the inspection of the thinning 6 of the heat exchanger tube of the boiler has been described. However, the tube group thinning inspection apparatus of the present invention is not limited in application by the material and shape of the subject, and has a length. Even when a pipeline of several kilometers is divided into several tens of meters and sequentially inspected, it can be widely applied.

  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 obvious, so the present invention has industrial applicability. high.

It is a figure which shows the structure of the pipe group thinning inspection apparatus concerning the Example of this invention. It is a figure which shows the detailed structure of the probe unit of the tube group thinning inspection apparatus of FIG. 1, Fig.2 (a) is sectional drawing of an instep probe group, FIG.2 (b) is the ot probe group. It is sectional drawing. It is sectional drawing which shows the structure of the vibrational absorption member of the pipe group thinning inspection apparatus of FIG. An example of the thinning evaluation curve stored in the database of the tube group thinning inspection apparatus in FIG. 1 is shown. FIG. 4 (a) shows the correlation between the received signal amplitude ratio and the ratio of the thinning diameter to the depth. FIG. 4B is a diagram for evaluating the loss rate from the received signal amplitude and the thinning position at the excitation frequency of 120 KHz, and FIG. 4C is a diagram for evaluating the loss rate from the reception signal amplitude and the thinning position at the excitation frequency of 40 KHz. It is a figure which shows the flow which correct | amends the crimping | compression-bonding force of the pipe group thinning inspection apparatus of FIG. It is a figure which shows the flow which performs the thinning inspection of the heat exchanger pipe | tube of a boiler with the pipe group thinning inspection apparatus of FIG. A group of transducers with signals transmitted in one direction out of signals transmitted from the probes constituting the former probe group of the tube group thinning inspection apparatus in FIG. It is a figure explaining the effect | action canceled by the signal which the probe which comprises comprises. 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 2 butt weld 3a, 3b header 4a, 4b fillet weld
5 Bending part 6 Thinning part 11a-11d, 12a-12d Cylinder 13 Holder 14, 16a, 16b, 18 Bolt 15a, 15b Sensitivity compensation test piece 17 Vibration absorbing member 19 Excitation signal generating part 20 Excitation signal delay control part 21 Excitation signal Phase controller
22 Received Signal Processing Unit 23 Fluid Pressure Control Unit 24 Pressurized Fluid Generation Unit 25 Database 26 Display Unit
27a to 27d Probe units constituting the upper probe group
28a to 28d Probe units 29a to 29d and 30a to 30d constituting the Otsu probe group Sealing materials 31a to 31d and 32a to 32d Vibration elements
33a to 33d, 34a to 34d Acoustic coupling member 35 Elastic rubber

Claims (9)

An even number of probe units (27a) for transmitting a horizontally polarized transverse wave having a specific frequency appropriately selected from a plurality of frequencies propagating in the axial direction of the test tube (1) and receiving the reflected wave -27d) and the same number of probe units (28a-28d) as the number of probes constituting the former probe group are included, and the test tube A holder (13) attached to the outer surface of (1);
In order to transmit the horizontally polarized transverse waves transmitted from the even number of probe units (27a to 27d, 28a to 28d) constituting the pair of probes A and B to the test tube (1), Acoustic coupling members (33a-33d, 34a-34d) provided between the probe units (27a-27d, 28a-28d) and the test tube (1);
Sensitivity compensation test specimens (15a, 15b) provided at both ends of the holder (13) in order to reflect the horizontally polarized transverse waves of the test tube (1) transmitted from the pair of probe A and B respectively. When,
A vibration absorbing member (17) for selectively absorbing a signal accompanied by an outer surface displacement among transmission / reception signals propagating through the test tube (1);
Pressure bonding means for pressing each of the probe units (27a to 27d, 28a to 28d) constituting the pair of probe pairs by the fluid pressure of the pressurized fluid independently against the outer surface of the test tube (1). (A) and
An excitation signal generator (19) for sending an excitation signal of the specific frequency to an even number of probe units (27a to 27d) constituting the upper probe group;
An excitation signal phase controller (21) for phase-controlling the excitation signal of the specific frequency sent from the excitation signal generator (19) by 180 degrees;
The P / C time (C: velocity of the transversely polarized wave propagating through the test tube (m / sec), P: pair of Kootoi pair in the signal of the specific frequency sent from the excitation signal phase controller (21) Excitation signal delay control for giving a delay of the distance (m) between the probe groups and sending the excitation signals of the above frequency to the even number of probe units (28a to 28d) constituting the second probe group Part (20);
Refer to the reflected signals from at least one of the sensitivity compensation test bodies (15a, 15b) received by the even number of probe units (27a-27d, 28a-28d) that respectively constitute the pair of probes B and B Obtained by adding the signal received by the former probe group and the function received by the former probe group and the function of controlling the pressurized fluid pressure and transmitting it to the crimping means (A). The function of evaluating the thinning existing in the test tube (1) with reference to the database (25) for thinning evaluation prepared in advance based on the received signal of the frequency, and displaying it on the display unit (26) A received signal processing unit (22) having:
A tube group thinning inspection apparatus characterized by comprising:   The holder (13) enclosing the pair of probes A and B is configured to be separable and can be attached to any position of the test tube (1). The tentacle units (27a to 27d, 28a to 28d) are vibrating elements (31a to 31d, 31a to 31d, which transmit horizontal waves of horizontal polarization incident simultaneously and in the same phase from equidistant positions on the outer circumference of the test tube (1). 32. The tube group thinning inspection apparatus according to claim 1, further comprising 32a to 32d).   The acoustic coupling members (33a to 33d, 34a to 34d) are arranged on the side in contact with the test tube (1) of all the probe units (27a to 27d, 28a to 28d) constituting the pair of probes A and B. A vibration element that is provided and can be replaced with a material that can be easily adapted to the surface roughness of the test tube (1), and whose acoustic impedance value constitutes the probe unit (27a to 27d, 28a to 28d) The pipe group thinning inspection apparatus according to claim 1, which approximates the acoustic impedance values of (31a to 31d, 32a to 32d) and the test tube (1).   The vibration absorbing member (17) includes an elastic body (35) that is in direct contact with the outer surface of the test tube (1), is configured to be split, and can be attached to any position of the test tube (1). The tube group thinning inspection apparatus according to claim 1.   The pressure-bonding means (A) includes a pressure fluid generator (24) that generates a pressure fluid, a fluid pressure controller (23) that controls the pressure of the pressure fluid by a control signal from the reception signal processor (22), Cylinders (11a to 11d, 12a to 12d) provided in the holder (13), and the cylinders (11a to 11d, 12a to 12d) connect the vibration elements (31a to 31d, 32a to 32d) with test tubes ( The pipe group thinning inspection apparatus according to claim 1, wherein the pipe group thinning inspection apparatus has a function of a piston that presses against a surface of 1). The excitation signal delay control unit (20) transmits the excitation signal sent from the excitation signal phase control unit (21) to the P / C time (C: the velocity of the transversely polarized wave propagating through the test tube (1) ( m / sec), P: a distance between the pair of probe groups B and B (m)) is sent to the probe units (28a to 28d) constituting the probe group, and the received signal processing unit ( 22), wherein the signals received by the probe unit constituting Kinoesagu probe group (probe unit constituting the signal and Party B probe group received in 27a-27d) (28a to 28d) P 2. The tube group thinning inspection apparatus according to claim 1, which has a function of adding as a signal shifted by a time of / C time .   The database (25) shows the correlation between the ratio of the thinning diameter and the depth using the amplitude ratio of the received signal at a specific frequency as a parameter, and the loss rate using the amplitude of the received signal and the thinning position at a specific frequency as a parameter. The tube group thinning inspection apparatus according to claim 1, comprising data indicating: The former probe is reflected by reflecting the transmission signal from the probe unit (27a to 27d) of the former probe group of the former group of tube thinning inspection apparatus according to claim 1 from the thinning position of the test tube (1). Group probe units (27a-27d)
The transmission signal from the probe unit (27a to 27d) of the former probe group is transmitted to the probe unit (28a to 28d) of the second probe group for P / C time (C: horizontal propagation through the test tube). Receive the wave by delaying by the velocity of the transverse wave of polarized wave (m / sec), P: the distance between the pair of probes B and B (m)),
The signals reflected from the thinning position of the test tube (1) received by the probe unit (27a to 27d) of the former probe group are received by the probe unit (28a to 28d) of the Otsu probe group. The amplitude of the higher order mode wave from the thinning position is set to 1 or less and the amplitude of the received signal of the lowest order twist mode wave is doubled in advance by adding the above signals as a signal shifted by P / C time. A tube group thinning inspection method characterized by evaluating the thinning of the test tube (1) with reference to the prepared database (25) for thinning evaluation . An even number of probe units constituting Party Otsu pair of probes groups, respectively (27a-27d, 28a to 28d) from the horizontal polarization of a particular frequency which propagates in the axial direction of the test tube (1) Transverse waves are transmitted, the reflected waves from the sensitivity compensation test body (15b) on the side referring to the reflected signal are received by the probe units (27a to 27d, 28a to 28d), and the reflected waves are referred to and crimped. With the probe units (27a to 27d, 28a to 28d), the pressing fluid pressure in the direction of the test tube (1) of the probe units (27a to 27d, 28a to 28d) by means (A) is corrected sequentially. The transmission signal transmitted and transmitted to the test tube (1) is controlled to make the intensity of the transmission signals propagating through the test tube (1) uniform with each other . Tube group thinning inspection method.

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