JPH05149928A - Method and apparatus for non-destructive inspection with ultrasonic wave, and probe used in apparatus thereof - Google Patents

Abstract

PURPOSE:To obtain a non-destructive inspecting apparatus, which can detect the presence or absence of liquid simply and positively by using ultrasonic waves. CONSTITUTION:A non-destructive inspecting apparatus detects the presence or absence of detecting liquid Wtr, which is filled in a gap D between steel plates 14 and 16 of double-shell tank formed of the inner and outer shell steel plates 14 and 16 by using ultrasonic waves. This apparatus comprises a probe 100 and a measuring instrument 300. The probe 100 comprises a transmitting piezoelectric transducer 105T and a receiving piezoelectric transducer 105R. The transducer 105T converts an electric signal for an ultrasonic wave into the ultrasonic wave and transmits the wave into the outer shell steel plate 16 or the inner shell steel plate 14 at the constant angles. The transducer 105R receives the reflected wave and converts the wave into the electric signal. The measuring instrument 300 feeds the vibrating signal to the transmitting piezoelectric transducer 105T, forms the gate signal after the specified time based on the reflected signal from the shell steel plate on the side to be measured in the reflected electric signal from the receiving piezoelectric transducer 105R and detects the presence or absence of the detecting liquid Wtr based on the presence or absence of reflected-wave-signal group SIn-b, which is inputted in the gate signal period.

Description

Detailed Description of the Invention

[0001] The present invention relates to a detection method for detecting whether a layer laminated on a solid layer is a liquid layer or an air ((Air)) layer by using ultrasonic waves, and in particular, the inner shell tank and the outer shell tank are fixed. Method and apparatus for ultrasonic non-destructive inspection capable of non-destructively inspecting the presence / absence of a filling liquid filled between an inner shell tank and an outer shell tank in a double shell tank formed at intervals It relates to the probe used for.

[0002]

2. Description of the Related Art The Petroleum Federation's technical subcommittees and related associations are
With the aim of introducing an underground tank of S double shell specification, we have conducted demonstration experiments on this SS double shell structure tank (hereinafter referred to as "double shell tank"). Although there are various verification tests on the safety of this double-shell tank, a confirmation test of the amount of deformation due to underground burial load is particularly important. As a result of this confirmation test, there is no structural problem with the double shell tank,
Since a leak detection system can be added, it has been found that this leak detection system can constantly monitor the leak of the tank, and has a preventive effect against the leak of oil and the detection liquid. Based on these results, the supervising ministry revised the Cabinet Order on the regulation of dangerous goods. As a result, the SS double shell tank (S
S400) has been approved as an underground tank.

FIG. 11 is a view showing the shape of a tank at the time of manufacturing the above-mentioned double shell tank. 12 is the X of FIG.
It is a X-ray sectional view.

As can be seen from these figures, the double shell tank 11 comprises an inner shell tank 13, an outer shell tank 15 and various auxiliary structures 17. The inner shell tank 13 is formed of an inner shell steel plate 14 in a cylindrical shape, and the outer shell tank 15 is formed of an outer shell steel plate 16 in a cylindrical shape. These tanks 1
A gap D is formed between the holes 3 and 15. Further, both the tanks 13 and 15 are also configured by mirror plates including an inner shell steel plate 14 and an outer shell steel plate 16 with respect to the mirror portion. The auxiliary structure 17 includes the air vent 17a of the inner shell tank 13, the supply port 17b into the inner shell tank 13, and the detection liquid W in the gap D between the inner shell tank 13 and the outer shell tank 15.
A tr filling port 17c and other necessary structures are provided.

Further, the gap D between the outer and inner shell steel plates 14 and 16 of the double shell tank 11 is usually filled with 30% ethylene glycol liquid as a detection liquid Wtr. The leak detection system uses the detection liquid W when a hole is formed due to corrosion of the shell steel plates 14 and 16.
It is a system that confirms abnormalities early by changes in tr.

By the way, the detection liquid Wtr is stored in the double-shell tank 11.
When air is present in the gap D between each inner shell tank 13 and the outer shell tank 15 when filling, the air expands or contracts due to the underground environment temperature and the oil temperature after underground burying, and the leak detection system detects it. There is a possibility that the level of the liquid Wtr will be affected and that the detection liquid Wtr will leak and an error will be made that is judged to be an oil leak. For this reason, there is a demand for a method for confirming whether or not the detection liquid Wtr is reliably filled when the double-shell tank 11 is manufactured, and for easily checking the degree of injection of the detection liquid Wtr. The inspection area is the inspection area 19 in FIG. 11.

Therefore, conventionally, when the manufacturing of the double shell tank 11 is completed, a gap D between the inner shell tank 13 and the outer shell tank 15 is produced.
There has been a demand for a method of simply detecting an air pool that occurs when the detection liquid Wtr is filled in the inside. Conventionally, as shown in FIG. 12, a sensor 21 that vertically emits an ultrasonic wave from an electric signal of a predetermined oscillation frequency and converts the reflected wave into an electric signal,
While generating an oscillating electric signal to the sensor 21,
The electric signal of the reflected wave from the sensor 21 is taken in and detected by an apparatus including an air checker 23 having a function of detecting the air pool.

This detection method is different from the presence / absence of a defect in a material in a non-destructive inspection using ultrasonic waves, and can detect whether the opposite side is a liquid or a gas through the outer / inner shell steel plate. The measurement procedure is described in.

In the above-mentioned double shell tank 11, as shown in FIGS. 13 and 14, the outer shell steel plate 16 has a plate thickness of, for example, 3.2 [mm] or 4.5 [mm], and The plate thickness of the inner shell steel plate 14 is, for example, 6.0 or 8.0 [mm]. The gap D between the shell steel plates 14 and 16 is kept at 3.2 [mm], and the gap D is shown in FIG.
In this case, the detection liquid Wtr is filled, and in the case of FIG. 14, only the air (Air) is filled.

In the conventional detection method by the vertical method, as shown in FIGS. 13 and 14, the sensor 21 by the vertical method is brought into contact with the surface of the outer shell steel plate 16. When a signal is given from the air checker 23 to the sensor 21, the sound wave emitted from the sensor 21 is multiply reflected inside the outer shell steel plate 16 to become a multiple reflected wave P, which is detected by the sensor 21. In addition, as shown in FIG. 13, the inner and outer shell steel plates 1
Boundary surface I between the detection liquid Wtr and the inner shell steel plate 14 between 4 and 16
The reflected wave group In-b from NB is also detected by the sensor 21.

The detected signal is detected as a reflected wave signal group SIn-b in the multiple reflected wave signal group SP in the outer shell steel plate 16 as shown in FIG. Further, when there is no detection liquid Wtr as shown in FIG. 14, the detection signal from the sensor 21 is as shown in FIG.
As shown in FIG. 6, only the multiple reflection wave signal group SP of the steel plate is formed.

[0012]

According to the above-described conventional detection method, the reflected wave signal SIn-b of the detection liquid Wtr is disturbed by the multiple reflection wave signal group SP of the outer shell steel plate. However, there is a drawback in that it is difficult to detect the reflected wave signal SIn-b from the device due to the poor signal-to-noise ratio.

Further, in the above-mentioned conventional detection method, a method of detecting the presence or absence of the detection liquid Wtr by comparing the waveform when the detection liquid Wtr is present and the waveform when the detection liquid Wtr is not present is conceivable. However, it was not reliable because it could not be clearly judged, and it was not possible to adopt this method.

The present invention is intended to improve the above-mentioned drawbacks, and it is possible to easily and accurately detect an air reservoir generated when the detection liquid is filled between the outer and inner shell steel plate walls at the completion of manufacturing the double shell tank. It is an object of the present invention to provide a non-destructive inspection method and apparatus using ultrasonic waves, and an object thereof is to provide an optimal probe for use in the destructive inspection method and apparatus.

[0015]

In order to achieve the above-mentioned object, the invention of claim 1 provides a transmitting oscillator and a receiving oscillator, which are provided so as to face each other with a predetermined inclination, and , A solid layer and a liquid layer or an air layer laminated on this solid layer are irradiated with ultrasonic waves at a predetermined angle, and the reflected wave from the measured layer is received by the receiving transducer. Then, from among the received reflected waves from the measured layer, when the longitudinal wave reflected wave from the measured liquid layer following the transverse reflected wave from the measured solid layer is detected, the measured solid layer is detected. It is characterized by detecting that the layer laminated on is a liquid layer.

According to the second aspect of the present invention, there is provided a nondestructive inspection method for nondestructively detecting the presence or absence of the detection liquid filled in the gap between the inner and outer shell steel plates of the double shell tank composed of the inner and outer shell steel plates by ultrasonic waves. Ultrasonic waves are incident at a predetermined angle from the outer shell steel plate or inner shell steel plate of the tank, and whether there is a longitudinal wave reflected wave following the transverse wave reflected wave from the outer shell steel plate or the inner shell steel plate among the reflected waves reflected On the basis of the above, the presence or absence of the detection liquid is detected.

The third aspect of the present invention is characterized in that the predetermined angle at which the ultrasonic waves are incident from the outer shell steel plate of the tank is set between 35 degrees and 40 degrees with respect to the incident surface.

According to a fourth aspect of the present invention, there is provided an apparatus for performing nondestructive inspection by ultrasonic waves for the presence or absence of the detection liquid filled in the gap between the inner and outer shell steel plates of the double shell tank composed of the inner and outer shell steel plates. Ultrasonic waves are incident from the shell steel plate at a predetermined angle, a probe that receives a reflected wave from the double shell tank, and a reflected wave electric signal from the probe are received. From this reflected wave electric signal, A reflected wave signal from the probe-side shell-to-be-measured shell is detected, a gate signal is formed after a predetermined time from the attenuation of the reflected wave signal, and the detection liquid is detected depending on the presence or absence of the reflected wave signal received during the gate signal period. Measuring circuit to detect the presence or absence of
It is composed of and.

According to a fifth aspect of the present invention, a transmitting oscillator for injecting an ultrasonic wave into the DUT and a receiving oscillator for receiving a reflected wave from the DUT have an inclination angle. It is characterized in that they are integrally provided facing each other.

[0020]

According to the first aspect of the present invention, it can be accurately detected whether or not the stack to be measured includes the liquid layer.

According to the second aspect of the invention, the acoustic impedance Z (density ρ × sonic velocity C) of the steel plate and the acoustic impedance Z of the liquid are set.
Since the sound pressure reflectance is large at the boundary surface between and, in the conventional measurement method, most of the incident sound waves are reflected at the boundary surface between the steel plate and the liquid, and are interfered by the multiple reflection of the steel plate, and At the point where it is difficult to distinguish the presence or absence of air, the presence or absence of the detection liquid is detected by obliquely injecting ultrasonic waves and detecting the reflected wave from the detection liquid that arrives later than the steel plate.

According to the third aspect of the invention, the incident angle of the ultrasonic wave incident on the steel plate is set to 35 to 40 degrees to obtain the optimum reflected wave from the detection liquid.

An ultrasonic non-destructive inspection apparatus according to a fourth aspect of the present invention comprises a probe and a measuring instrument.
An ultrasonic wave is obliquely incident on the steel plate from the probe, the reflected wave is detected by the probe, and the presence or absence of the reflected wave after a lapse of a predetermined time from the detection signal is detected by a measuring instrument to detect liquid. The presence or absence of is displayed.

In the probe of the fifth aspect of the present invention, since the transmission oscillator and the reception oscillator are integrated at an angle, ultrasonic waves are obliquely incident and obliquely reflected. The reflected wave coming can be detected reliably.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an ultrasonic non-destructive inspection apparatus of the present invention.

In the embodiment shown in FIG. 1, the ultrasonic vibration signal is converted into ultrasonic waves and the object to be measured (outer shell steel plate 1
6) The transducer for transmission 105T and the transducer for reception 1 for receiving the reflected wave from the object to be measured (the steel plate 16 for the outer shell) at a position different from that of the transducer for transmission 105T and converting it into an electric signal.
A probe 100 having a built-in 05R, and a reflected wave signal from the surface of the object to be measured on the probe side out of the received signals from the probe 100, which gives an ultrasonic vibration signal to the probe 100. And a measuring device 300 that detects the presence or absence of the detection liquid based on the presence or absence of the reflected wave signal that is incident during this gate signal period.

Here, the measuring device 300 is the transmitter 30.
1, reception amplifier 302, S detection gate circuit 303, shell steel plate (OB) gate circuit 304, OB detection circuit 305,
Mark drive circuit 306, OB mark display 307,
Detection liquid reflection signal (IN-B) gate circuit 308, IN-
B detection circuit 309, mark drive circuit 310, IN-
A B-mark display device 311, a liquid crystal digital display device 312, a mode switching device 313, an alarm circuit 314, and a buzzer 315 are provided. Further, the S detection gate circuit 303 includes a gate selector section 320, a surface wave detection section 321 and an OB gate starting point section 322.

These elements have the following configuration. That is, the measuring instrument 300 supplies a vibration signal from the transmitter 301 to the probe 100 via the transmission terminal T. The detection signal from the probe 100 is supplied to the reception amplifier 302 via the reception terminal R. The output signal of the reception amplifier 302 is supplied to the OB gate circuit 304 via the S detection gate circuit 303.
The output signal of the OB gate circuit 304 is the OB detection circuit 30.
5 and the IN-B gate circuit 308. The OB detection circuit 305 has a circuit configuration in which a reflected wave signal from the shell steel plate is detected and supplied to the mark drive circuit 306. The mark drive circuit 306 drives the OB mark display 307 for display according to the magnitude of the reflected signal. The IN-B gate circuit 308 is designed to open the gate of the OB gate circuit 304 for a certain period of time after closing the gate, and to pass the signal when there is a reflected wave signal from the detection liquid Wtr. The IN-B detection circuit 309 determines the magnitude of the reflected wave signal when the reflected wave signal is present.
Supply to 0. When there is the reflected wave signal, the mark drive circuit 310 causes the mark of the IN-B mark display 311 to be lit and displayed, the size of the mark to be displayed on the liquid crystal digital display 312, and the reflected wave signal to be displayed. If not, the mark on the IN-B mark display 311 is turned off and the liquid crystal digital display 312 is set to "0".
0:00 ”is displayed. When there is no reflected wave signal, the alarm circuit 314 operates and the buzzer 315 sounds.

2 to 5 show the structure of a probe 100 according to an embodiment of the present invention. FIG. 2 is a front view showing the same, FIG. 3 is a bottom view of the same, FIG. 4 is a side view of the probe, and FIG. 5 is a sectional view of the probe taken along the line YY in FIG.

The probe of this embodiment has spherical oscillators for transmission and reception therein, and is a two-oscillator bevel probe in which point-convergent bevel probes which face each other are integrated. Is configured.

On the upper surface of the housing case 101 in the drawing,
A transmission connector 102T and a reception connector 102R are provided. Inside the housing case 101, as shown in FIG. 3 and FIG.
Wedges 104T and 104R are provided on the left and right with the boundary as a boundary. The connectors 102T and 102R are connected via matching coils 106T and 106R, respectively. The transmitting oscillator 105T and the receiving oscillator 105R are configured by, for example, point-convergent oscillators. The probe 10
0 uses a point-convergence type oscillator, so the focal length can be set arbitrarily depending on the diameter and radius of curvature of the oscillator.
It is selected according to the difference in the thickness of the inner and outer shell steel plates and the inspection request from either the outer or inner shell steel plate side.

The operation of the embodiment having such a structure will be described based on FIGS. 1 to 5 with reference to FIGS.

<Experimental Detection Waveform by the Probe 100 of the Present Invention> First, as shown in FIG. 5, the thickness of the inspection side shell steel plate (in FIG. 5, the inspection from the outer shell steel plate 16) is 5.7 [. mm)
And when the thickness of the gap D is 1.1 [mm] and is parallel to each other, when the detection liquid Wtr or air (Air) is filled in the gap D, one embodiment of the present invention A waveform diagram obtained by using the probe 100 of FIG.

That is, FIG. 6A shows the inner and outer shell steel plates 14, 16
6B is a waveform diagram when the detection liquid Wtr is not present and there is air (Air), and FIG. 6B is a waveform diagram when the detection liquid Wtr is filled. It can be seen from the observed waveform that multiple reflected wave groups of the detection liquid on the IN-B surface are clearly detected. That is, the transmitted ultrasonic signal ST, the reflected wave signal SS from the outer shell steel plate 16 surface, the reflected wave signal group SU from the outer shell steel plate 16, and the multiple reflected wave group SI _n - _b generated by the detection liquid are clearly shown in the waveform diagram. (Fig. 6
(B)).

From the results of this experiment, it can be seen that the use of the probe 100 of the present invention makes it possible to detect the presence or absence of the detection liquid Wtr even with a small gap D.

<Explanation of Operation of Probe 100 Regarding Presence / Absence of Detection Liquid Wtr> Next, a basic operation of detecting the presence / absence of the detection liquid Wtr using the probe 100 of the present invention will be described.

FIG. 7A is an explanatory view of the detection principle by the probe 100 when the detection liquid Wtr is filled between the inner and outer shell steel plates 14 and 16, and FIG. 6 is an explanatory diagram of a detection principle by the probe 100 when the detection liquid Wtr is not filled between the shell steel plates 14 and 16. FIG. Figure 8
FIG. 8A shows a detection signal diagram in FIG.
7B shows the detection signal waveform diagram in FIG. 7B.

As shown in FIG. 7A, the sound wave transmitted from the transmitting oscillator 105T has a longitudinal wave UP in the wedge 104T.
Propagated by Ta, converted into transverse wave UPTb in the outer steel plate 16,
It is incident on the steel plate at a refraction angle of 40 degrees. The sound waves obliquely incident reach the boundary OB surface between the outer shell steel plate 16 and the detection liquid Wtr,
Is reflected. The reflected sound wave is reflected in the outer steel plate 16 and follows the path of the reflected wave UPRb → the reflected wave UPRa and is received by the receiving transducer 105R. This reflected wave becomes a reflected wave in the outer shell steel plate 16 and appears as a reflected wave signal group SU as shown in FIG.

On the other hand, in FIG. 7A, the sound wave propagated to the detection liquid Wtr without being reflected by the boundary line OB is a longitudinal wave UP.
The mode is converted to Tc, and the boundary surface with the inner steel plate 14 IN−
Reflected at B, reflected wave UPRc → reflected wave UPRb → reflected wave U
The signal is received by the receiving oscillator 105R following the path PRa. This reflected wave becomes the reflected wave from the detection liquid Wtr, and the multiple reflected wave signal group SIn-b, SIn-b ', SIn- is shown in FIG.
It appears as a reflected wave signal from the IN-B plane, which is shown as b ″, ...

When there is no detection liquid Wtr, as shown in FIG. 7B, the boundary surface O between the outer steel plate 16 and the air (Air) is detected.
Since it is completely reflected by B, there is no multiple reflection wave of the reflection wave In-b on the IN-B surface, and as shown in FIG.
It can be seen that only the reflected wave signal SU on the OB surface of No. 6 is present, and the difference between the presence and absence of the detection liquid 3 is remarkable.

As described above, the probe 100 of the present invention is characterized in that the number of times of multiple reflection waves on the steel plate can be reduced as compared with the conventional vertical method sensor 21, and the presence / absence of the detection liquid Wtr is S / N. It can be seen that it has the ability to detect well and that the presence / absence of the detection liquid can be surely confirmed.

<Description of Ultrasonic Nondestructive Inspection Apparatus According to the Present Invention> Next, the operation of the ultrasonic nondestructive inspection apparatus according to the embodiment of the present invention shown in FIG. 1 will be described.

Here, the measuring instrument 300 constituting the non-destructive inspection apparatus of the present invention may use an ultrasonic flaw detector together,
Non-destructive with the addition of the function as an air checker, utilizing the function of plate thickness measurement as it is, based on a dedicated air checker and an ultrasonic thickness gauge for the purpose of downsizing and weight reduction for easy on-site handling. Figure 1 as an inspection device
The block diagram shown in FIG.

FIG. 9 is a time chart for explaining the ultrasonic non-destructive inspection apparatus of the present invention, and FIG. 10 shows a display example of a liquid crystal display used in the ultrasonic non-destructive inspection apparatus. It is a figure.

First, the operation with the detection liquid Wtr will be described.

The measuring device 300 is connected to the probe 10 by a cable.
0 is connected. From the transmitter 301 of the measuring instrument 300 via the cable, the transmitting transducer 105T of the probe 100
Supply a vibration signal to. As shown in FIG. 7A, the sound wave transmitted from the transmitting oscillator 105T propagates in the wedge 104T as a longitudinal wave UPTa and obliquely enters the outer shell steel plate 16 (40 degrees in this embodiment). It is incident. The sound waves obliquely incident reach the boundary OB surface between the outer shell steel plate 16 and the detection liquid Wtr and are reflected. The reflected sound wave is transmitted to the receiving transducer 105.
Received by R. The reflected wave received by the receiving transducer 105R is supplied to the receiving amplifier 302 of the measuring instrument 300 as a reflected wave signal group SU (see FIG. 8A). On the other hand, in FIG. 7A, the sound wave propagated to the detection liquid Wtr without being reflected by the boundary line OB is the boundary surface IN− with the inner shell steel plate 14.
It is reflected by B and received by the receiving transducer 105R. This reflected wave group In-b is input to the reception amplifier 302 of the measuring instrument 300 as a multiple reflected wave signal group SIn-b, SIn-b ′, SIn-b ″, ... As shown in FIG. These signal groups SU, SIn-b, SIn-b ′, SIn-b ″, ... Are amplified to a certain level by the reception amplifier 302 and supplied to the S detection gate circuit 303. S detection gate circuit 303
Then, the gate selection unit 320 performs gate selection (time t _{2 to} t ₇ ) by the surface wave gate delayed by, for example, 5 [μS] from the input time t _{1 of the} transmission ultrasonic signal ST, and removes the transmission ultrasonic signal ST. By inputting the output to a flip-flop circuit (not shown), the reception amplifier 3
The output that rises at the rise (time t ₃ ) of the reflected wave signal SS (the reflected wave from the surface of the inner shell steel plate 14 when inspecting from the inside) output from the surface of the outer shell steel plate 16 is the surface wave detection unit 321. Can be obtained at. This rising is input to the mono-multi (OB gate starting point portion 322) and is set as a starting point for opening the OB gate circuit 304 at a time position where the reflected wave signal SS from the surface of the outer shell steel plate 16 is attenuated (time t ₄ ).
Further, (time t ₅₎ at the time of closing the gate of the OB gate circuit 304 will open that IN-B gate circuit 308.

The time when the OB gate circuit 304 is closed is set at a point where the reflected wave signal group SU of the outer shell steel plate 16 or the inner shell steel plate 14 becomes minimum. When the reflected wave signal group SU of only the steel plate detected in the OB gate circuit 304 is input to the OB detection circuit 305, the OB detection circuit 305 determines that the reflected wave signal group US is equal to or higher than a certain level. Output as if there is a group SU. When there is this output, the mark drive circuit 306 turns on the mark of the OB mark indicator 307. The lighting of this mark indicates that the probe 100 is normally in contact with the outer shell steel plate 16, for example. This mark display is used to check whether the probe 100 is normally in contact with the steel plate.

Further, the IN-B gate circuit 308 is opened from the rear end (time t ₅ ) of the OB gate 304 as described above because the detected reflected wave is after the outer shell steel plate bottom wave (SU signal). In consideration of the case where the detection layer becomes thick, the closing time of the gate of the -B gate circuit 308 is set to the reflected wave signal group S.
In-b, SIn-b ', SIn-b ", ... are set after the period in which the liquid can be reliably taken in. When the detection liquid is present (Fig. 7 (a)), the IN-B gate circuit is used. By 308
Only the reflected wave signal groups SIn-b, SIn-b ′, SIn-b ″, ... Are extracted and input to the IN-B detection circuit 309. IN-
The B detection circuit 309 uses the reflected wave signal groups SIn-b and SIn.
-b ', SIn-b ", ... Are above a certain level, the signal is supplied to the mark drive circuit 310 and the alarm circuit 314. In this case, the mark drive circuit 310
The NB mark indicator 311 is turned on. At this time, the mark drive circuit 310, as shown in FIG. 10A, has its reflected wave signal groups SIn-b, SIn-b ', SIn-.
b ”, ... Digitally displays with the signal.

Next, the operation without the detection liquid Wtr will be described.

In the absence of the detection liquid Wtr, as shown in FIG. 7B, the ultrasonic wave from the transmitting oscillator 105T is completely reflected by the boundary surface OB between the outer steel plate 16 and the air (Air). , There is no multiple reflected wave of the reflected wave group In-b on the IN-B surface, and only the reflected wave signal group SU on the OB surface of the outer shell steel plate 16 as shown in FIG. Circuit 30
8 has no output, the alarm circuit 314 is activated and the detection liquid Wtr
Is alerted.

That is, this reflected wave signal group SU is measured by the measuring instrument 3
00 receiving amplifier 302, receiving amplifier 302
Then, it is amplified to a certain level and supplied to the S detection gate circuit 303. In the S detection gate circuit 303, similarly to the above-described operation, gate selection is performed by a surface wave gate delayed by 5 [μS] from the transmission ultrasonic signal ST (time t ₁ ) (time t _{2 to} t ₇ ), The output is input to the flip-flop circuit. At the rising output of the reflected wave signal SS from the surface of the outer steel plate 16 of the output from the receiving amplifier 302 (time t ₂ ), this rising is input to the OB gate starting point 322 and the time for the reflected wave signal SS to decay. At the position (time t ₄ ), the OB gate circuit 304 is used as a starting point for opening. Further, at the time of closing the gate of the OB gate circuit 304 (time t ₅ ), the IN-B gate circuit 3
08 will open.

When the reflected wave signal SU detected only in the steel plate in the OB gate circuit 304 is input to the OB detection circuit 305, the OB detection circuit 305 indicates the reflected wave signal group SU when the OB detection circuit 305 is at a certain level or higher. Output as. When there is this output, the mark drive circuit 306 turns on the mark of the OB mark indicator 307. From this, it can be seen that the probe 100 is normally in contact with the outer steel plate 16.

The IN-B gate circuit 308, as described above,
It opens from time t ₅ and closes at time t ₇ , but the reflected wave signal group SIn
Since there is no -b, the IN-B detection circuit 309 does not detect anything. Therefore, since a signal indicating that nothing is detected is output from the IN-B detection circuit 309, the mark drive circuit 310 turns off the IN-B mark indicator 311 and
Moreover, the liquid crystal digital display 312 is displayed as "00:00" as shown in FIG. Also, at this time,
Since the alarm circuit 314 is also provided with a signal indicating that the reflected wave signal group SIn-b is not detected, the alarm circuit 314 sounds the buzzer 315. As a result, the detection liquid Wtr
You can also confirm that there is no sound.

By operating in this way, it becomes possible to detect the presence or absence of the detection liquid Wtr.

Here, the air checker of the present embodiment described above is operated from the outer shell steel plate 16 having a thickness of 4.5 mm, and the gap between the outer and inner shell steel plates is changed at an inclination angle of 2 degrees. Table 1 below shows the measurement results of the case.

[0057]

[Table 1]

In Table 1, the mark "◯" indicates that the device of the present invention operates normally, and the mark "x" indicates that the device of the present invention does not operate normally. The column A shows the operation result when the probe 100 is oriented in the axial direction of the double shell tank 11. The column B shows the operation result when the probe 100 is set in the direction perpendicular to the axial direction of the double shell tank 11.

As can be seen from Table 1, in the apparatus of the present invention, the inner shell steel plate 14 and the outer shell steel plate 16 of the double shell tank 11 are used.
It can be seen that the operation is reliably performed when the distance W of the gap D is 2.6 [mm] to 12.8 [mm]. Experimentally, in the apparatus of the present invention, it has been confirmed that the operation of the air-checker is normal up to a detection liquid gap of about 13 mm at an inclination angle of 6 degrees.

As can be seen from the above-mentioned measurement results, the apparatus of the present invention can accurately and reliably detect the presence or absence of the detection liquid Wtr in the double shell tank 11.

In the above-mentioned embodiment, the probe 100 is used.
From the above, an example in which ultrasonic waves are incident on the outer shell steel plate 16 at 40 degrees has been described, but the operational effects of the present invention can be sufficiently achieved even if they are incident at an angle of, for example, about 35 degrees to 40 degrees.

In the above-described embodiment, the probe 100 is used.
Although the method has been described in which the measurement is performed by contacting the outer shell steel plate 16 with the outer shell steel plate 16, the measurement can also be performed by contacting the inner shell steel plate 14 from the inside of the double shell tank 11. Of course, double shell tank 1
It is also possible to detect from the mirror part of 1.

[0063]

As described above, according to the first aspect of the invention, the presence or absence of the liquid layer is detected by detecting the reflected wave from the liquid layer that obliquely enters the ultrasonic wave and arrives later than the steel sheet. Therefore, the presence or absence of the liquid layer can be surely and accurately confirmed.

According to the second aspect of the present invention, the presence or absence of the detection liquid is detected by detecting the reflected wave from the detection liquid which arrives at a delay from the steel sheet by injecting ultrasonic waves obliquely.
The presence or absence of the detection liquid can be confirmed reliably and accurately.

According to the third aspect of the invention, the incident angle of the ultrasonic wave incident on the inner shell steel plate or the outer shell steel plate is 35 to 35.
Since the angle is set to 40 degrees, it is possible to obtain the optimum reflected wave depending on the presence or absence of the detection liquid.

The ultrasonic non-destructive inspection apparatus according to the fourth aspect of the present invention comprises a probe and a measuring instrument.
Ultrasonic waves are obliquely incident on the steel plate from the probe, the reflected wave of this is detected by the probe, and the presence or absence of the reflected wave in the predetermined gate period is detected from the detection signal by the measuring instrument. The presence or absence of the detection liquid can be accurately determined, the configuration is simplified, the number of parts can be reduced, and the device can be conveniently carried.

In the probe of the fifth aspect of the present invention, since the transmitting oscillator and the receiving oscillator are integrated at an angle, ultrasonic waves can be incident obliquely and reflected obliquely. The reflected waves that come in can be detected reliably, and since they are integrated, handling is convenient.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic non-destructive inspection apparatus of the present invention.

FIG. 2 is a front view showing a partially broken example of the probe of the present invention.

FIG. 3 is a bottom view showing an embodiment of the probe of the present invention.

FIG. 4 is a side view showing an embodiment of the probe of the present invention.

FIG. 5 is a cross-sectional view showing an embodiment of the probe of the present invention.

FIG. 6 is a waveform diagram when measured with the probe of the present invention.

FIG. 7 is an explanatory diagram of measurement with the probe of the present invention.

8 is a waveform chart showing the measurement results of FIG.

FIG. 9 is a waveform diagram for explaining an operation when a double-shell tank is measured by the ultrasonic non-destructive inspection device of the present invention.

FIG. 10 is an explanatory diagram showing a display example of measurement results by the ultrasonic non-destructive inspection device of the present invention.

FIG. 11 is a front view showing an example of a double-shell tank.

FIG. 12 is a sectional view taken along line XX of FIG.

FIG. 13 is an explanatory diagram of measurement when a conventional sensor has a detection liquid.

FIG. 14 is an explanatory diagram of measurement when a conventional sensor does not have a detection liquid.

FIG. 15 is a waveform diagram when measured in FIG.

16 is a waveform diagram when the measurement is performed in FIG.

[Explanation of Codes] 11 Double Shell Tank 13 Inner Shell Tank 14 Inner Shell Steel Plate 15 Outer Shell Tank 16 Outer Shell Steel Plate 100 Probe 101 Housing Case 103 Shield Plate 104T Wedge 104R Wedge 105T Transmitter Transducer 105R Receiver Transducer 300 measuring instrument 301 transmitter 302 receiving amplifier 303 S detection gate circuit 304 OB gate circuit 305 OB detection circuit 307 OB mark display device 308 IN-B gate circuit 309 IN-B detection circuit 310 mark drive circuit 311 IN-B mark display Device 312 LCD digital display

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Morio Nakano 2-6-31 Kamishinjo, Nakahara-ku, Kawasaki-shi, Kanagawa 2-6-31, Teitsu Electronics Laboratories, Inc. (72) Mitsuru Iwahashi 2 Kamishinjo, Nakahara-ku, Kawasaki-shi, Kanagawa −6−31 Inside Teito Denshi Laboratories (72) Inventor Kaoru Kase 10-7 Nishinakacho, Tsurumi-ku, Yokohama-shi, Kanagawa Nihon Engineering Service Co., Ltd. (72) Inventor, Bonkichi Kawada Tsurumi, Yokohama, Kanagawa Ward Market Nishinakamachi 10-7 Japan Engineering Service Co., Ltd.

Claims (5)

[Claims] 1. A transmission oscillator and a reception oscillator are provided so as to face each other with a predetermined angle of inclination, and the transmission oscillator includes a solid layer and a liquid layer or an air layer laminated on the solid layer. Ultrasonic waves are incident on the measurement stack at a predetermined angle, reflected waves from the stack to be measured are received by the receiving oscillator, and from among the received reflection waves from the stack to be measured, When detecting a longitudinal wave reflected wave from the measured liquid layer subsequent to the transverse wave reflected wave from the measured solid layer, it is characterized by detecting that the layer laminated on the measured solid layer is a liquid layer Non-destructive inspection method using ultrasonic waves. 2. An inspection method for nondestructively detecting the presence or absence of a detection liquid filled in a gap between inner and outer shell steel plates of a double shell tank composed of inner and outer shell steel plates by ultrasonic waves. Ultrasonic waves are incident from the steel plate at a predetermined angle, and the presence or absence of the above-mentioned detection liquid is detected based on the presence or absence of the longitudinal wave reflected wave following the transverse wave reflected wave from the outer or inner shell steel plate among the reflected waves reflected. An ultrasonic non-destructive inspection method characterized by the above. 3. The ultrasonic wave according to claim 2, wherein the predetermined angle at which the ultrasonic wave is incident from the outer shell steel plate of the tank is set between 35 degrees and 40 degrees with respect to the incident surface. Non-destructive inspection method by. 4. A non-destructive inspection device for detecting the presence or absence of a detection liquid filled in a gap between inner and outer shell steel plates of a double shell tank composed of inner and outer shell steel plates by ultrasonic waves. A probe which receives ultrasonic waves at a predetermined angle and receives a reflected wave from the double shell tank, and a reflected wave electric signal from the probe, and the probe from the reflected wave electric signal The reflected wave signal from the child-side shell to be measured is detected, a gate signal is formed after a predetermined time from the attenuation of this reflected wave signal, and the presence or absence of the detection liquid is determined by the presence or absence of the reflected wave signal received during this gate signal period. An ultrasonic non-destructive inspection device comprising a measuring circuit for detecting and. 5. A transducer for transmitting an ultrasonic wave to an object to be measured and a transducer for receiving a reflected wave from the object to be measured are integrated so as to face each other with an inclination angle. A probe for a non-destructive inspection apparatus using ultrasonic waves, which is provided in the.