JP2005291962A - Ultrasonic remote flaw detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately and precisely measure the reduction of a thickness and the presence of any damage caused by the oxidation deterioration of a structure, and a degree thereof from a remote site by an ultrasonic wave, while holding stably a contact medium between an ultrasonic sensor and an inspected face for a long period. <P>SOLUTION: This ultrasonic flaw detection system of the present invention has a container 15 attached to an inspected object 12, a contact medium supply means 16 for supplying the contact medium 14 into the container 15, the ultrasonic sensor 11 stored in the container 15, and contacting with the surface of the inspection object 12, a cylinder device 17 provided in the container 15 to bring the ultrasonic contact with the surface of the inspection object 12, and a stirring means 30 provided in an operation rod 28 extended from the cylinder device 17, and the contact medium 14 stored in the container 15 is convection-moved by the stirring means 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to ultrasonic nondestructive flaw detection technology for ultrasonic flaw detection of structures such as metals, non-metals, and ceramics from a remote location, and in particular, the presence or absence or degree of damage to structures such as steel towers, iron bridges, and oil tanks. The present invention relates to an ultrasonic remote flaw detector that can be determined from a remote location.

  Structures (structures) made up of steel towers, steel bridges, oil tanks, etc., will undergo oxidation over 5 years and 10 years, and the thickness of the iron structural materials will become thinner and weaker, and the degree of damage May develop and there is a risk of collapse. Accurate diagnosis of the remaining life of structures is an important issue for social safety.

  In order to recognize the degree of deterioration of a structure and determine the presence or absence and degree of damage, measure the thickness of the material constituting the structure, diagnose the presence and degree of damage, and It is necessary to accurately diagnose how much the physical and physical strength has decreased.

  As this type of ultrasonic flaw detector, there is an ultrasonic flaw detector described in Japanese Patent Laid-Open No. 9-292373 and an ultrasonic flaw detector described in Japanese Patent Laid-Open No. 2-2933.

  The former ultrasonic flaw detection technology is used for ultrasonic flaw detection tests in narrow spaces that are difficult for humans to access, such as the gap between the control rod drive mechanism (CRD) housing in the reactor pressure vessel and the CRD stub tube. The coplanar liquid is pressurized and supplied. Because the coplanar liquid sealing technology for this ultrasonic flaw detection test can encapsulate the coplanar liquid in a narrow gap, which is a narrow part, finally the welded part of the CRD stub tube and the reactor pressure vessel mirror is used. It is described that an ultrasonic flaw detection test can be performed. However, there is no specific disclosure on how to conduct an ultrasonic flaw detection test for narrow areas.

In addition, the latter ultrasonic flaw detection apparatus includes a storage tank for coplanar liquid, and the coplanar liquid stored in the storage tank is transferred between the probe and the surface to be inspected of the structure regardless of the posture of the storage tank. In the meantime, it is inspected for the presence of stress corrosion cracking or the like while moving along the weld line of the structure.
Japanese Patent Laid-Open No. 9-292373 JP-A-2-2933

  The former ultrasonic flaw detection technology has disclosed the technology of pressurizing and supplying the coplanar liquid to the narrow part that is difficult for humans to access. There is no disclosure of flaw detection technology.

  On the other hand, in the latter ultrasonic flaw detector, the probe is pressed and moved by the lifting mechanism to the inspection surface (flaw detection surface) side of the structure, and the probe is pressed by the compressed air from the compressed air supply device. However, since the pressing force of the probe depends on the air pressure of the compressed air, the pressing force is not uniform and varies.

  If the contact force that presses the probe against the surface to be inspected varies, coplanar liquid leaks from between the probe and the surface to be inspected, or air flows between the probe and the surface to be inspected. Then, the air that flows in may mix with the coplanar liquid, and it may be difficult to perform accurate and accurate ultrasonic flaw detection on the surface to be inspected.

  In addition, structures composed of steel towers, steel bridges, oil tanks, etc. are often large-sized, and the thickness of members on the top of the structure and high side walls is measured, and the presence and extent of damage is diagnosed. It is difficult to perform flaw detection with a poor scaffold.

  In the latter ultrasonic flaw detector, a plurality of pairs of outer legs and inner legs that can be adsorbed to the surface to be inspected are provided, and the inner and outer legs are operated alternately by the cooperative action of each leg and the moving mechanism. Although it is designed to be moved by walking, it requires complicated mechanisms and sequence control for leg walking, and it is difficult to move and hold the ultrasonic flaw detector in places with poor scaffolding. It was difficult to stably hold the flaw detector.

  In addition, if the ultrasonic flaw detector is installed at a predetermined location for a long period of time, the thickness of the structure, the presence / absence of damage, and the degree of measurement are regularly measured to predict the lifetime of the entire structure, attach the probe. Even if the viscosity of the coplanar liquid is high and the viscosity is large, the coplanar liquid will flow down over time, or because of oxidative degradation due to oxygen in the atmosphere, the ultrasonic waveform sensitivity will greatly decrease, and the plate thickness will be measured. There was a risk that the measurement of the presence or absence or degree of damage would be inaccurate. If the coplanar liquid flows down from the gap between the probe and the surface to be inspected and is depleted, there is a possibility that it is difficult to obtain an ultrasonic echo signal.

  The present invention has been made in consideration of the above-described circumstances, and can stably hold a contact medium between an ultrasonic sensor and a surface to be inspected for a long period of time, and the thickness is reduced due to oxidative deterioration of a structure. It is another object of the present invention to provide an ultrasonic remote damage apparatus capable of nondestructively measuring the presence or absence and degree of damage from a remote location.

  Another object of the present invention is to make ultrasonic testing of the surface to be inspected easily and accurately periodically by bringing the ultrasonic sensor into contact with the surface to be inspected with a predetermined pressing force stably and accurately. The object is to provide an ultrasonic remote flaw detector capable of performing the above.

  Another object of the present invention is to prevent the contact medium from leaking between the ultrasonic sensor and the surface to be inspected or the air of the contact medium from being mixed in advance, and to accurately and accurately prevent the surface to be inspected. An object of the present invention is to provide an ultrasonic remote flaw detection apparatus that can easily perform good ultrasonic flaw detection.

  In order to solve the above-described problem, an ultrasonic remote flaw detection apparatus according to the present invention includes a container attached to an object to be inspected and a contact medium that supplies the contact medium into the container. A supply means, an ultrasonic sensor housed in the container and capable of contacting the surface of the object to be inspected, and a cylinder provided in the container and pressing and contacting the ultrasonic sensor to the surface of the object to be inspected And a stirring means provided on an operating rod extending from the cylinder device, and the contact medium accommodated in the container is convectively moved by the stirring means.

  Further, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention is configured such that the container is detachably and liquid-tightly attached to an object to be inspected, This is a sealed container constituting a sealed state.

  Moreover, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention includes, as described in claim 3, the cylinder device includes an air cylinder that houses a piston, and an ultrasonic sensor that includes the piston. A spring pressing means for biasing the spring to the side, and an air supply means for applying an air pressure for retracting the piston against the pressing force of the spring pressing means, and the ultrasonic sensor is inspected by the spring pressing means. It is pressed against the surface of the body.

  In order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention includes, as described in claim 4, the contact medium supply unit includes a storage tank that stores the contact medium. The contact medium stored in the tank is configured to be injected into the container using the gas pressure of inert gas or nitrogen gas.

  Further, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention provides an aqueous medium for supplying water as a contact medium into the container. A supply means is provided, and the water medium supply means supplies water as a contact medium.

  Further, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention includes, as described in claim 6, the aqueous medium supply means, a filtration device that removes salt and impurities from seawater, It has a water supply line which guides the water filtered by this filtration apparatus into a container, and a check valve provided in this water supply line.

  Further, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention is provided with negative pressure means for assisting the supply of the contact medium in the container, as described in claim 7, and this negative pressure is provided. The means is provided with a negative pressure pump in the discharge line from the container.

  Further, in order to solve the above-described problem, the ultrasonic remote flaw detection apparatus according to the present invention is configured such that, as described in claim 8, the ultrasonic sensor receives an oscillated ultrasonic echo waveform, while receiving Provided with a controller for operating the contact medium supply means when the signal level of the ultrasonic echo signal received by the signal processing device is below a predetermined value. It is.

  Moreover, in order to solve the above-described problems, the ultrasonic remote flaw detection apparatus according to the present invention is characterized in that the ultrasonic sensor housed in the container has a fluid contact with the sensor tip. It is equipped with an elastic film that prevents the medium from being washed away.

  In the ultrasonic remote flaw detection apparatus according to the present invention, the contact medium (casplant liquid) in the container attached to the object to be inspected is convectively moved by the stirring device driven by the cylinder device, and the contact medium is stably supplied over a long period of time. Because it is possible to maintain it, it is possible to perform ultrasonic inspection accurately from a remote location in a non-destructive manner in the thickness reduction, damage, etc. due to oxidative degradation of structures such as underwater and steel towers that workers cannot access by ordinary inspection be able to.

  Further, the ultrasonic sensor can be pressed and contacted with the surface of the object to be inspected with a predetermined pressing force, so that ultrasonic inspection of the surface to be inspected can be performed regularly and easily with high accuracy.

  Furthermore, the contact medium can be stably held between the ultrasonic sensor and the surface to be inspected, and leakage and oxidation of the contact medium can be prevented, so that the ultrasonic inspection can be accurately performed with high detection accuracy of the surface to be inspected.

  An embodiment of an ultrasonic remote flaw detector according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an embodiment of the ultrasonic remote flaw detection apparatus according to the present invention. This ultrasonic remote flaw detection apparatus 10 uses an ultrasonic sensor 11 to remotely detect the thickness reduction due to oxidative degradation of a structure (structure) that is difficult for an operator to approach during routine inspections such as steel towers, steel bridges, and oil tanks. It is a device that can measure non-destructively from the ground for a predetermined period, for example, every month. The ultrasonic remote flaw detection apparatus 10 is detachably tightened and attached via an attachment belt 13 that is paired with a structure inspection object 12.

  The ultrasonic remote flaw detection apparatus 10 supplies a transparent cylindrical container 15 that stores a coplanar liquid 14 as a contact medium, an ultrasonic sensor 11 that is stored in the container 15, and the coplanar liquid 11 in the container 15. The operation of the contact medium supply means 16, the cylinder device 17 that makes the ultrasonic sensor 11 press contact with the object to be inspected 12, the gas exhaust means 18 that discharges the gas in the container 15, and the cylinder device 17 are controlled. Controller 19.

  The cylindrical container 15 is formed of a transparent resin material, for example, an acrylic resin material. The container 15 has a handle 21 protruding outward in the diametrical direction on the front side. By tightening the handle 21 with a mounting belt 22, the sealed container 15 is liquid-tightly attached to the inspected object 12 and sealed. It becomes a sealed container. The hermetic container 15 may be mounted through a sealing material rich in elasticity in order to improve hermeticity.

  By making the container 15 have a sealed structure, it is possible to prevent oxidative degradation of the coplanar liquid 14 accommodated in the sealed container 15. By preventing this oxidative deterioration, it is possible to prevent a decrease in detection sensitivity of the ultrasonic echo waveform by the ultrasonic sensor 11.

  A cylinder device 17 is integrally or integrally provided on the back side of the hermetic container 15. The cylinder device 17 includes a cylindrical air cylinder 24, a piston 25 accommodated in the cylinder 24, a coil spring 26 as a spring pressing means for pressing the piston 25 toward the sealed container 15, and a spring of the spring 26. An air supply means 27 for retracting the piston 25 in a direction against the force and an operating rod 28 protruding from the piston 25 into the sealed container 15 are provided. The ultrasonic sensor 11 is attached to the tip of the operating rod 28 and fixed. The spring pressing means 26 may be provided with a fluid supply means instead of the coil spring. The cylinder device 17 may be provided in the sealed container 15.

  The actuating rod 25 is provided with an agitating fin 30 as an agitating means in a sealed container 15 on the way, and the agitating fin 30 is reciprocated by the reciprocating motion of the piston 25 to agitate the coplanar liquid 14 stored in the sealed container 15. The convection movement (convection circulation) is caused in the sealed container 15.

  The air supply means 27 includes a compressor 33 that compresses air, an air supply line 35 that supplies high-pressure air discharged from the compressor 33 to the cylinder chamber 34 of the air cylinder 24, and an electromagnetic wave provided in the air supply line 35. The solenoid valve 36 is controlled to be opened and closed by the controller 19. By opening the electromagnetic valve 36, high-pressure air discharged from the compressor 33 is supplied to the cylinder chamber 34. By supplying the high-pressure air, the piston 25 can be retracted against the spring force of the coil spring 26, and the ultrasonic sensor 11 is retracted from the object to be inspected 12 and separated.

  Reference numeral 37 denotes a piston ring having an elastic sealing function, and reference numeral 38 denotes a liquid-tight or air-tight seal ring.

  The ultrasonic sensor 11 is provided with a rubber film 39 as an elastic film so as to cover the sensor tip. The rubber film 39 is provided in order to prevent the coplanar liquid 14 that is a fluid contact medium interposed between the ultrasonic sensor 11 and the inspection object 12 from being lost. The Kaplan liquid 14 adhered to the surface of the inspection object 12 can be prevented from flowing due to the sealing property of rubber, and can be stably held for a long time.

  A glycerin-based acoustic matching material that allows the ultrasonic wave from the ultrasonic sensor 11 to easily pass through the inspection object 12 is used for the coplanar liquid 14.

  The ultrasonic sensor 11 includes a probe that oscillates an ultrasonic wave when a voltage having a high power supply frequency is applied. The ultrasonic waves oscillated from the probe toward the surface to be inspected 12 are reflected by the density difference due to the surface and internal defects and returned as an echo wave. It is detected by the sensor 11.

  The ultrasonic echo wave detected by the ultrasonic sensor 11 is sent as an echo signal through the signal line 40 to a signal processing device 41 such as a personal computer for signal processing. The signal processing result is displayed on the display device 42.

  By confirming the signal processing image by the display device 42 and by automatic signal processing by the signal processing device 41, the degree of thickness reduction due to oxidative deterioration of the material of the inspection object 12 and damage deterioration of the inspection object 12 can be determined. It can be measured from a remote location for a predetermined period, for example, every month or every year.

  On the other hand, the contact medium supply means 16 for supplying the coplanar liquid 14 into the sealed container 15 through the medium supply line 43 includes a storage tank 44 for storing the coplanar liquid 14 as the contact medium, and helium / argon in the storage tank 44. And a pressurized gas tank 46 as a gas supply source for supplying the inert gas or nitrogen gas through the gas injection line 45. The gas injection line 45 and the coplanar liquid supply line 43 are provided with solenoid valves 47 and 48 that are controlled to open and close by the controller 19. The pressure in the pressurized gas tank 46 is maintained higher than the pressure in the sealed container 15.

  Further, considering the case where ultrasonic flaw detection is performed on seawater or the iron structure 12 existing in the water from a remote place, the contact medium supply unit 16 includes an aqueous medium supply unit 50 using seawater or the like as a contact medium as necessary. Provided.

  The water medium supply means 50 is a water that is immersed in seawater to remove salt and impurities, and water that supplies filtered water (pure water) filtered by the filter 51 as a contact medium into the sealed container 15. A supply line 52 and a negative pressure means 53 for making the inside of the sealed container 15 into a negative pressure so that the filtered water is smoothly taken into the sealed container 15 are provided. For the filtration device 51, for example, a hollow fiber membrane filter is used as a filtration filter, and seawater and impurities flow into the sealed container 15 to prevent the drive mechanism from being damaged.

  The water supply line 52 is provided with a check valve 54, while the negative pressure means 53 has a discharge line 55 extending from the gas space side of the sealed container 15, and a vacuum (negative pressure) pump 56 is provided to the discharge line 55. Is provided. The discharge line 55 is also provided with an electromagnetic valve 57 and is controlled to open and close by the controller 19.

  Further, the check valve 54 is provided in the water supply line 52 to prevent the contact medium 14 from flowing out of the sealed container 15, while the filtration device 51 is provided at the inlet of the water supply line 52 to provide the sealed container 15. It is a means for removing salt and impurities from the seawater flowing in and purifying it into the sealed container 15.

  A gas discharge line 58 is branched from the upstream side of the electromagnetic valve 56 to the discharge line 55 constituting the negative pressure means 53 of the sealed container 15, and the gas discharge line 58 is open to the atmosphere. This gas discharge line 58 is also provided with an electromagnetic valve 59 that is controlled to open and close by the controller 19.

  Next, the operation of the ultrasonic remote flaw detector 10 will be described.

This ultrasonic remote flaw detection apparatus 10 has a structure 12 such as iron, an iron bridge, a petroleum tank, a gas tank, etc., and a thickness reduction of constituent materials due to oxidative degradation of the test specimen 12 and the presence or absence of internal defects. The ultrasonic remote flaw detection apparatus which periodically measures ultrasonic waves from a remote place attaches the airtight container 15 to the object to be inspected 12 in a liquid-tight and detachable manner by the attachment belt 13. The ultrasonic sensor 11 housed in the sealed container 15 may be attracted to the surface to be inspected using the magnetic force (attraction force) of a magnet provided around the sensor. Here, the piston 25 is pressed and moved by the spring force of the coil spring 26 accommodated in the cylinder device 17, and the ultrasonic sensor 11 is pressed against the surface to be inspected 12 via the operating rod (piston rod) 28. Make contact.

  At that time, a predetermined amount of glycerin-based coplanar liquid 14 is supplied into the sealed container 15 by the contact medium supply means 16. When the cylinder device 17 is driven, the actuating rod 28 reciprocates and the agitation fins 30 agitate the coplanar liquid 14 supplied into the sealed container 15, thereby enabling circulation by the convective movement of the coplanar liquid 14.

  The ultrasonic sensor 11 is attached to the tip of the operating rod 28 of the cylinder device 17, and the ultrasonic sensor 11 provided at the tip of the operating rod 28 by driving the cylinder device 17 is covered by the object 12 to be inspected. Contact with the inspection surface enables measurement of the thickness of the object 12 to be inspected by ultrasonic waves, the presence or absence of internal defects, and the degree of damage.

  The ultrasonic flaw detection of the inspection object 12 by the ultrasonic remote flaw detection apparatus 10 oscillates ultrasonic waves from the probe of the ultrasonic sensor 11 toward the inspection object 12 in the state shown in FIG. By detecting ultrasonic echo waves reflected from the surface and internal defects of the optical sensor with the ultrasonic sensor 11 and sending the detected echo signal to the signal processing device 41 for signal processing, the thickness and deterioration of the material of the inspection object 12 , The presence of internal defects, and the size can be measured from a remote location.

  As an example, a cylindrical container 15 having an inner diameter of 38 mmφ, an outer diameter of 50 mmφ, and a height of 50 mm was brought into liquid-tight contact with the inspected object 12 having a thickness of 30 mm, and the thickness of the inspected object 12 was measured by ultrasonic waves. A spring push type air cylinder 24 having a cylinder diameter of 25 mm and a piston stroke of 10 mm was prepared for the cylinder device 17, and the ultrasonic sensor 11 having a diameter of, for example, 10 mm was used.

  In a state where no air pressure is applied from the air supply means 27 to the cylinder device 17, the ultrasonic sensor 11 stably presses the surface to be inspected of the inspection object 12 with a predetermined spring pressing force by the spring action of the spring 26. It is kept in contact.

  In order to release the ultrasonic sensor 11 from the pressed state on the surface of the object to be inspected, if the air supply means 27 supplies air pressure greater than the spring force of the spring 26 into the air cylinder 24, the ultrasonic sensor 11 is inspected. It can be separated from the body 12.

  When air pressure is applied to or removed from the air cylinder 24 of the cylinder device 17, the cylinder device 17 is driven and the ultrasonic sensor 11 moves, so that the Kaplan liquid 14 as a contact medium also flows. When the hermetic container 15 is formed of a transparent acrylic resin, red ink or paint is dropped on the coplanar liquid 14 and the movement of the coplanar liquid 14 by driving the cylinder device 17 is observed. Although the fluid movement was only near the vicinity of the ultrasonic sensor 11, it was found that when the stirring fin 30 was provided, convection movement occurred from the tip of the ultrasonic sensor 11 toward the stirring fin 30.

  When the flaw detection inspection is performed for a long time with the ultrasonic remote flaw detection apparatus 10 attached to the inspection object 12, the coplanar liquid 14 attached to the tip of the ultrasonic sensor 11 is depleted or the sensing function is deteriorated. Come on.

  However, in the ultrasonic remote flaw detection apparatus 10 shown in FIG. 1, when the sensitivity of the echo waveform of the ultrasonic wave detected by the ultrasonic sensor 11 is lowered to a certain level or less, the decrease in the waveform sensitivity is detected by the signal processing device 41. Since the signal control system 60 for driving and controlling the cylinder device 24 is constructed by transmitting the detection signal to the controller 19 and detecting the detection signal by the display device 42, the cylinder device 17 can be driven and controlled. It is possible to effectively and effectively prevent depletion of the sensor and deterioration of the sensing function by the ultrasonic sensor 11.

  Due to the drive control of the cylinder device 17, the piston 25 reciprocates by the action of the spring force of the coil spring 26 and the air pressure from the air supply means 27, thereby agitating and convection of the Kaplan liquid 14 in the sealed container 15. The liquid 14 can be supplied between the ultrasonic sensor 11 and the inspection object 12.

  When the supply of air pressure from the air supply means 27 into the cylinder chamber 34 of the cylinder device 17 is stopped, the ultrasonic sensor 11 is pressed by a predetermined force, for example, 1.2 kg, by the spring force of the coil spring 26. The detection sensitivity of the echo waveform by the sensor 11 can be recovered.

  At that time, since the required amount of the coplanar liquid 14 as the contact medium is filled in the sealed container 15, a system for constantly supplying the contact medium as in the conventional ultrasonic flaw detector is not necessary.

  Actually, a signal control system in which the ultrasonic echo waveform by the ultrasonic sensor 11 is difficult to detect and the echo signal detection sensitivity is lowered is detected by the signal processing device 41 or the like, and the drive control of the cylinder device 17 is performed by the controller 19. When 60 was constructed, it was possible to circulate convection of the coplanar liquid 14 in the sealed container 15 and increase the detection sensitivity of ultrasonic echoes. In addition, since it is not necessary to constantly supply the coplanar liquid into the sealed container 15, it is not necessary to supply the coplanar liquid, the workability is simplified, and a stable ultrasonic remote flaw detection system is obtained.

  Further, in the ultrasonic remote flaw detection apparatus 10 shown in FIG. 1, the supply of the coplanar liquid 14 as the contact medium into the sealed container 15 is performed by bringing the storage tank 44 into a pressurized state higher than the atmospheric pressure. be able to. By setting the inside of the sealed container 15 to atmospheric pressure or higher, it is possible to prevent inflow of moisture and air. For this reason, the coplanar liquid 14 in the sealed container 15 does not undergo inflow deterioration or oxidation deterioration due to moisture outside the sealed container 15 or moisture in the atmosphere. Can be installed.

  Furthermore, the case where glycerin is prepared as the coplanar liquid 14 as the contact medium and this glycerin is supplied to the sealed container 15 from a remote place will be described.

  In this case, the controller 19 opens the electromagnetic valve 45 that allows inert gas or nitrogen to flow into the sealed storage tank 44, then the electromagnetic valve 57 to the vacuum pump 56, and then the coplanar liquid 17 to the sealed container 15. The supplied solenoid valves 47 are opened.

By opening the electromagnetic valve 45, a necessary pressure, for example, 1 kg / cm ² (gauge pressure) is applied to the sealed storage tank 44 with an inert gas or nitrogen gas, and then the electromagnetic valve 57 attached to the sealed container 15 is turned on. The inside of the sealed container 15 is depressurized by opening the vacuum pump 56. When the solenoid valve 47 is opened in this negative pressure state, a pressure difference between the pressure in the storage tank 44 and the pressure in the sealed container 15 is generated, and the glycerin as the coplanar liquid 14 stored in the storage tank 44 flows smoothly. And flows into the sealed container 15.

  The coplanar liquid 14 is caused to flow into the sealed container 15, and the electromagnetic valve 57 to the vacuum pump 56 is closed when the ultrasonic sensor 11 observes an ultrasonic echo indicating the plate thickness of the inspection object 12. When the electromagnetic valve 57 is closed, the supply pressure from the storage tank 44 is in an equilibrium state with the pressure in the sealed container 15 and the supply of the coplanar liquid 14 is stopped. In the experiment over two weeks, seawater as a contact medium was always present in the sealed container 15.

  At this time, since the pressure in the sealed container 15 is higher than the atmospheric pressure outside the sealed container 15, it is possible to prevent the rainwater and seawater outside the sealed container 15 from flowing into the sealed container 15 in advance and accurately.

  In this case, it is not necessary to provide the aqueous medium supply means 50 shown in FIG.

  An example of a system in which an ultrasonic remote flaw detector 10 according to the present invention is provided on the surface of an object to be inspected 12 of an iron structure existing in seawater, and the thickness, presence / absence, and degree of damage of the iron structure are measured by an ultrasonic sensor. explain. An example in which seawater is used as the contact medium is shown. The overall configuration is not different from that shown in FIGS. 1 and 2, and will be described with reference to FIGS.

  In this case, the water level of the seawater fluctuates due to high tide and low tide, and in the case of low tide, there is a case where the coplanar liquid (seawater) that is a contact medium is not supplied to the ultrasonic sensor 11. Moreover, since salt content exists in seawater, it is also considered that the constituent material of the ultrasonic sensor 11 is corroded.

  Therefore, when seawater is taken into the sealed container 15 as a contact medium, first, the vacuum pump 56 of the negative pressure means 53 is operated and the electromagnetic valve 57 is opened by the controller 19 in order to make the sealed container 15 have a negative pressure.

  By operating the vacuum pump 56, the inside of the sealed container 15 is reduced to a required pressure, for example, 150 mmHg, and a pressure difference is created so that seawater outside the sealed container 15 easily flows into the sealed container 15.

  On the other hand, in the filtration device 51, salt and impurities in the seawater are removed by a filtration filter. For example, a hollow fiber membrane filter is used as the filtration filter. After reducing the pressure in the sealed container 15 to, for example, 150 mmHg to 100 mmHg, the filtered seawater (pure water) flows into the sealed container 15 through the check valve 54 and flows into the sealed container 15 by the aqueous medium supply means 50. As a result, it was possible to fill the sealed container 15 with the aqueous medium in a required time, for example, about 30 seconds.

  A check valve 54 is provided in the aqueous medium supply means 50 so that the aqueous plant coplanar liquid taken into the sealed container 15 does not flow out of the sealed container 15. Further, the vacuum pump 56 in the sealed container 15 is maintained in a reduced pressure (negative pressure) state by the pump operation, and seawater (pure water) filtered by the filtration device 51 is always set to be allowed to flow.

  By setting the ultrasonic remote flaw detector 10 as described above, the chance of seawater flowing into the sealed container 15 at high tide increases, and even when no seawater exists outside the sealed container 15 at low tide, It is possible to prevent the coplanar liquid (water) from flowing out.

  Also in this ultrasonic remote flaw detector 10, there is no need to always operate the vacuum pump 56. The vacuum pump 56 may be pumped by the controller 19 when there is no more coplanar liquid (water) taken into the sealed container 15 and it becomes difficult to obtain an ultrasonic echo signal of a predetermined signal level. In this case, it is only necessary to automatically activate the pump of the vacuum pump 56 when necessary, so that the ultrasonic remote flaw detector 10 can be operated efficiently.

  Further, instead of providing the vacuum pump 56 in the negative pressure means 53, an air release line 58 may be provided.

  When the sealed container 15 is installed in a few meters in seawater, for example, 1 m or less, the water pressure acting on the inlet of the filtration device 51 of the aqueous medium supply means 50 and the inside of the sealed container 15 opened to the atmosphere by the atmosphere release line 58 A pressure difference is generated between the pressure and the seawater, and the seawater can flow from the filtering device 51 through the check valve 54 into the sealed container 15.

  In this example, by opening the electromagnetic valve 59 of the air release tube 57, the inside of the sealed container 15 becomes atmospheric pressure, which is smaller than the water pressure acting on the inlet of the filtering device 51, so that seawater exists outside the sealed container 15. As long as the seawater filtered by the filtration device 51 is introduced into the sealed container 15 as a contact medium.

  Next, a case where the sensor tip of the ultrasonic sensor 11 is covered with a rubber film 39 that is an elastic film is described.

  The ultrasonic echo signal from the inspected object 12 when the sensor tip of the ultrasonic sensor 11 is not covered with the rubber film 39 is measured, and the change with time is shown by a solid line a in FIG.

  Moreover, the ultrasonic echo signal from the to-be-inspected object 12 at the time of covering the sensor front-end | tip of the ultrasonic sensor 11 with the rubber-like film 39 is measured, and the time-dependent change is shown with the broken line b.

  FIG. 3 shows an ultrasonic measurement from a remote place for 4 months using the ultrasonic remote flaw detector 10 shown in FIGS. 1 and 2, but as can be seen from FIG. When the rubber film 39 is attached to the tip of the sensor, it has been found that the ultrasonic echo signal from the inspected object 12 has almost no decrease in detection sensitivity over a long period of time. In addition, when the rubber film 39 was not attached, the ultrasonic echo signal from the test object 12 did not cause a significant decrease in sensitivity for about 34 days and continued, but thereafter a large decrease in sensitivity occurred.

  When the ultrasonic sensor 11 is pressed against the surface of the inspection object 12 by the spring force of the coil spring 26 of the cylinder device 17, if the rubber film 39 is covered at the tip of the ultrasonic sensor 11 and covered, this rubbery material is covered. It has been found that the film 39 can hold the contact medium on the surface of the object to be inspected. When the rubber film 39 is attached, it has been found that the outflow of the contact medium can be effectively and effectively prevented from occurring due to the rubber's elasticity, and the contact medium can be held for a long period of time.

  In the embodiment of the ultrasonic remote flaw detection apparatus according to the present invention, an example in which the controller and the signal processing apparatus are separated from each other is shown. Also good.

Schematic which shows one Embodiment of the ultrasonic remote flaw detector based on this invention. Schematic which shows the state which driven the cylinder apparatus of the said ultrasonic remote flaw detector, and separated the ultrasonic sensor from the surface of the to-be-inspected object. The figure which graphed the time-dependent change of the ultrasonic echo waveform sensitivity at the time of mounting | wearing and removing the rubber film at the front-end | tip of the ultrasonic sensor with which the ultrasonic remote flaw detector which concerns on this invention is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ultrasonic remote flaw detector 11 Ultrasonic sensor 12 Inspected object 13 Mounting belt 14 Kaplan liquid (contact medium)
15 Sealed container 16 Contact medium supply means 17 Cylinder device 18 Gas exhaust means 19 Controller 21 Handle 24 Air cylinder 25 Piston 26 Coil spring (spring pressing means)
27 Air supply means 28 Actuating rod 30 Stirring fin (stirring means)
33 Compressor 34 Cylinder chamber 35 Supply line 36 Solenoid valve 39 Rubber chamber film (elastic film)
40 Signal Line 41 Signal Processing Device 42 Display Device 43 Medium Supply Line 44 Storage Tank 45 Gas Injection Line 46 Pressurized Gas Tank (Pressurized Gas Supply Source)
47 Solenoid valve 50 Water medium supply means 51 Filtration device 52 Water supply line 53 Negative pressure means 54 Check valve 55 Discharge line 56 Vacuum pump 57, 59 Electromagnetic valve 58 Atmospheric release line 60 Signal control system

Claims (9)

A container attached to the object to be inspected;
Contact medium supply means for supplying a contact medium into the container;
An ultrasonic sensor housed in the container and capable of contacting the surface of the object to be inspected;
A cylinder device that is provided in the container and presses and contacts the ultrasonic sensor so as to advance and retreat on the surface of the object to be inspected;
A stirring means provided on an operating rod extending from the cylinder device;
An ultrasonic remote flaw detection apparatus characterized in that a contact medium accommodated in a container is convectively moved by the stirring means. The ultrasonic remote flaw detector according to claim 1, wherein the container is a sealed container that is detachably and liquid-tightly attached to an object to be inspected to form a sealed state. The cylinder device operates an air cylinder that houses a piston, a spring pressing unit that biases the piston toward the ultrasonic sensor, and an air pressure that causes the piston to move backward against the pressing force of the spring pressing unit. The ultrasonic remote flaw detector according to claim 1, further comprising an air supply means, wherein the ultrasonic pressure sensor is brought into press contact with the surface of the object to be inspected by the spring pressing means. The contact medium supply means includes a storage tank for storing the contact medium, and is configured to inject the contact medium stored in the storage tank into the container using a gas pressure of an inert gas or a nitrogen gas. The ultrasonic remote flaw detector according to claim 1. The ultrasonic remote flaw detection according to claim 1, wherein the contact medium supply means includes an aqueous medium supply means for supplying water as a contact medium into the container, and the water medium supply means supplies water as the contact medium. apparatus. The water medium supply means includes a filtration device that removes salt and impurities from seawater, a water supply line that guides water filtered by the filtration device into a container, and a check valve provided in the water supply line. The ultrasonic remote flaw detector according to claim 5. 6. The ultrasonic remote flaw detector according to claim 1, wherein said container is provided with a negative pressure means for assisting the supply of the contact medium, and the negative pressure means includes a negative pressure pump in a discharge line from the container. The ultrasonic sensor receives a oscillated ultrasonic echo waveform, and is provided with a signal processing device that processes the received ultrasonic echo signal, and the signal level of the ultrasonic echo signal received by the signal processing device. The ultrasonic remote flaw detector according to claim 1, further comprising a controller that activates the contact medium supply means when is less than a predetermined value. 2. The ultrasonic remote flaw detection apparatus according to claim 1, wherein the ultrasonic sensor housed in the container is provided with an elastic film for preventing a fluid contact medium from flowing away at a sensor tip.

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