JP2006177738A - Tank inspection device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate flaw detection inspection for a tank provided with a heat insulating member. <P>SOLUTION: This device/method preferably includes inner vessel sheets 3, 4, 16 for forming a storage tank storing a content; an outer vessel sheet for forming a heat insulating layer arranged with the heat insulating material 7, in clearances with respect to the inner vessel sheets 3, 4, 16 therebetween; a measuring unit 10 arranged in the heat insulating layer and for flaw-detecting the the inner vessel sheets 3, 4, 16; and a propulsion devices 35, 36 for making the measuring unit 10 travel in the heat insulating layer. Cracks generated in the inner vessel sheets 3, 4, 16 are easily flaw-detected in such a tank 1, without extracting out the heat insulating material 7 and the content. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tank inspection apparatus and a tank inspection method, and more particularly, to a tank inspection apparatus and a tank inspection method used when inspecting a tank storing a liquid.

  An LNG tank that stores LNG is known. FIG. 9 shows a known LNG tank. The LNG tank 200 includes an outer tank side plate 202, an inner tank side plate 203, an inner tank annular plate 204, and a bottom cooler 205. The bottom cooler 205 is made of concrete and is fixed on the ground. The inner tank annular plate 204 is formed of a stainless steel plate and forms a disk. The inner tank annular plate 204 is fixed on the bottom cooler 205. That is, the bottom cooler 205 is disposed between the ground and the inner tank annular plate 204.

  The inner tank side plate 203 is made of a stainless steel plate and forms a cylinder. The inner tank side plate 203 is further welded and fixed to the surface of the inner tank annular plate 204 opposite to the side in contact with the bottom cold insulation portion 205 of the inner tank annular plate 204. That is, the inner tank side plate 203 and the inner tank annular plate 204 form a container that stores the LNG 210. The outer tank side plate 202 is formed of a stainless steel plate and forms a cylinder. The outer tub side plate 202 is further fixed to the ground such that the inner tub side plate 203, the inner tub annular plate 204, and the bottom cooler 205 are disposed therein.

  A heat insulating material is disposed in the gap between the outer tank side plate 202 and the inner tank side plate 203. The heat insulating material is formed of pearlite 206 and glass wool 207. The glass wool 207 is formed by forming glass fibers into a plate shape, and is fixed to the surface of the inner tank side plate 203 facing the outer tank side plate 202. The pearlite 206 is formed by solidifying grains formed from glassy rock, and is disposed between the glass wool 207 and the outer tank side plate 202.

  FIG. 10 shows a welded portion where the inner tank side plate 203 is joined to the inner tank annular plate 204. The end surface of the inner tank side plate 203 is fixed on the surface of the inner tank annular plate 204. A fillet 226 formed by welding is formed at a corner formed by the inner tank side plate 203 and the inner tank annular plate 204. For this reason, the inner tank annular plate 204 is formed of a portion inside the welded portion and a portion outside the welded portion. The portion inside the welded portion is in contact with the LNG 210 stored in the LNG tank 200. A portion outside the welded portion is in contact with the glass wool 207.

  In the LNG tank 200, after the LNG 210 is extracted and the outer tank side plate 202 and the pearlite 206 glass wool 207 are removed, the crack 227 generated in the inner tank annular plate 204 is detected using an ultrasonic flaw detector. It is desired to more easily detect a crack generated in the inner tank annular plate 204, the inner tank side plate 203 or the fillet 226.

  In Japanese Utility Model Laid-Open No. 61-152955, a rail is provided between the inner and outer tubs of the double-shell cryogenic tank over substantially the entire circumference, and one end of the rail extends into the opening provided in the outer tub so as to be closed. An inner tank inspection device for a double-shell cryogenic tank is disclosed in which an abnormality detection device for detecting an abnormality of a side plate of the inner tank is disposed so as to be able to travel on the rail by remote control.

  Japanese Patent Laid-Open No. 2001-59796 discloses an oil tank strength prediction apparatus and method for detecting cracks in a welded portion between a side plate and a bottom end plate of a petroleum tank and distortion of the side plate due to, for example, an earthquake. ing. The oil tank strength prediction device is an oil tank strength prediction device that detects cracks and side plate distortion in the vicinity of the welded portion between the side plate and bottom end plate of the oil tank. An optical fiber that is continuously laid in an axial direction, a strain measuring instrument that measures strain generated by the action of an external force through the optical fiber, and a side plate and a bottom end from the strain measured by the strain measuring instrument. And a monitoring device that monitors plastic strain and crack generation in the vicinity of the welded portion with the plate.

  Japanese Patent Application Laid-Open No. 2001-74713 discloses a tank inspection device that can inspect the bottom plate and side plate of a tank from the outer surface of the tank by a simple method without extracting the contents such as oil in the tank. . The tank inspection apparatus includes an apparatus main body having a measurement / control apparatus, an expansion / contraction holding means attached to the apparatus main body, a tire-type ultrasonic probe held by the expansion / contraction holding means, and the apparatus main body as a tank. And a moving means for moving along a traveling rail installed on the side plate or the bottom plate of the tire, and the measurement / control device detects the thinned portion based on the signal of the tire-type ultrasonic probe. , A distance meter for detecting the movement distance of the apparatus main body, calculation control means for inputting the signals of the distance meter and the ultrasonic flaw detector and specifying the position of the thinned portion, and calculation of the calculation control means Storage means for storing the results.

  Japanese Patent Laid-Open No. 2000-85886 discloses a tank internal inspection method and an inspection apparatus therefor that can be safely performed with a small number of man-hours without the need for draining the stored liquid and removing the flange lid. . The internal inspection method is an internal inspection method for a tank that stores liquid and has an opening with a lid. An inspection head having a light projecting means and an imaging means is inserted into the tank through the lid, and the inspection is performed via a cable. Operate the head from outside the tank.

  In JP 2000-33994 A, weld lines may be damaged by corrosion, thermal stress, earthquakes, etc. during long-term use of various tanks, but it is difficult to inspect after the use of tanks, Disclosed is an inspection system for a tank inner surface weld line that eliminates the disadvantage that various problems occur when the operation of the tank is stopped for inspection and the inspection cost is expensive. The tank inner surface weld line inspection system is an inspection system for inspecting a tank inner surface weld line during use of the tank, the rail member extending along a predetermined weld line on the tank inner surface, and a guide by the rail member. A carriage that is supported and equipped with an inspection device for inspecting a weld line; a wire that is guided by the rail member and is arranged to extend along the rail member; and is connected to the carriage; and the wire as a rail member Wire driving means for moving and driving the carriage along the rail member by driving in a predetermined direction along the rail.

  Japanese Patent Laid-Open No. 2000-2798 discloses an underwater defect of a lining storage tank that three-dimensionally inspects the position, shape, size, depth, and the like of a defective portion from the water surface without discharging pool water in the lining storage tank. An inspection device is disclosed. The underwater defect inspection device for the lining storage tank includes an underwater device installed in a lining storage tank in which water is stored and has a metal plate lining on the inner wall surface and bottom surface, a control device for controlling the underwater device, and an image from the underwater device. The underwater device mainly comprises an inspection mechanism unit, a drive mechanism unit, a suction mechanism unit, and a main body mechanism unit, and the control device attaches the underwater device to the metal plate lining. And a control mechanism for controlling the position of the drive mechanism section, and the image processing apparatus is a data processing function for inputting data from the inspection mechanism section, a three-dimensional image display function, an image display angle arbitrary change function, and a defect. It has a part shape image display function.

  Japanese Patent Application Laid-Open No. 2000-187004 discloses that it can be safely used in a flammable liquefied gas such as LNG and can move freely in the liquefied gas, and precisely observe the inner surface of the liquefied gas tank during its operation. An internal inspection device for a liquefied gas tank is disclosed. The internal inspection device for the liquefied gas tank includes an inspection head for inspecting the liquefied gas tank from the inside thereof, and a submerged propulsion device for moving the inspection head in the low-temperature liquefied gas. The low-temperature liquefied gas is heated and gasified, and the gasified gas is injected into the low-temperature liquefied gas to generate thrust.

  Japanese Patent Laid-Open No. 10-238699 discloses a tank interior that facilitates carrying in / out and fixing of an inspection device to / from a low temperature tank such as LNG, and allows the inspection device to be arbitrarily scanned from a remote location to enable internal inspection during operation. An inspection device is disclosed. The tank internal inspection device includes a cylindrical body having a fixing device fixed to the inner surface of the tank and a traveling device that travels on the inner surface of the tank, and is supported by the cylindrical body and scans the inspection probe and is free when power is lost. An arm device having a universal joint that is in a straight line with the cylindrical body, and a control device that is connected to the cylindrical body side by a cable and controls the operation of the inspection probe. An apparatus main body composed of an arm device has a cylindrical lateral arm connected to the distal end of the lateral arm via a cylindrical lateral arm and joint connected to the longitudinal arm via a cylindrical longitudinal arm and joint. The vertical arm and the horizontal arm bend the joint to form an L-shape, and the inspection probe is connected to the tip of the upright arm via the joint. And the traveling device is constituted by the vertical arm and a wheel unit provided on the horizontal arm at a position where a vertex of a triangle is formed when the vertical arm and the horizontal arm are L-shaped. It is characterized by being.

Japanese Utility Model Publication No. 61-152955 JP 2001-59796 A JP 2001-74713 A JP 2000-85886 A JP 2000-33994 A Japanese Patent Laid-Open No. 2000-2798 JP 2000-187004 A Japanese Patent Laid-Open No. 10-238699

  An object of the present invention is to provide a tank inspection device and a tank inspection method for detecting a tank more easily.

  In the following, means for solving the problems will be described using the reference numerals used in the best modes and embodiments for carrying out the invention in parentheses. This reference numeral is added to clarify the correspondence between the description of the claims and the description of the best mode for carrying out the invention / example, and is described in the claims. It should not be used to interpret the technical scope of the invention.

  The tank inspection device according to the present invention includes an inner tank plate (3, 4, 16) that forms a storage tank for storing a liquid and an insulating layer in which a heat insulating material (7) is disposed. The tank (1) provided with the outer tank plate formed in the gap between the inner tank plate and the inner tank plate (3, 4, 16). The tank inspection apparatus according to the present invention includes a measurement unit (10) (50) disposed in a heat insulation layer for flaw detection of the inner tank plates (3, 4, 16), and a measurement unit (10) (50) in the heat insulation layer. And propulsion devices (35, 36) (65, 66) for running on the vehicle. According to such a tank inspection apparatus, cracks generated in the inner tank plates (3, 4, 16) can be easily detected without taking the heat insulating material (7) and the liquid from the tank (1).

  The measurement units (10) and (50) are arranged in a gap between the contact medium tank (67) that stores the contact medium, and the inner tank plates (3, 4, 16) and the sensors (34) and (64) that oscillate ultrasonic waves. It is preferable to include pumps (38) and (68) for supplying the contact medium.

  The measurement unit (10) has a sharp beginning. At this time, the measurement unit (10) can smoothly move through the heat insulating material (7) by pushing away the heat insulating material (7) filled in the heat insulating layer.

The measurement unit (10) has a so-called streamline shape suitable for moving in the fluid, in which the surface in contact with the heat insulating material (7) is not angular and is gentle. At this time, when the measurement unit (10) is propelled through the heat insulating material (7), the resistance for generating a space through which the measurement unit (10) passes by pushing away the heat insulating material (7) is small, and the heat insulating material (7 ) Can move smoothly. That is, the expression “gentle” is not attached to minute unevenness like so-called “surface roughness”.
The surface of the measurement unit (10) that contacts the heat insulating material (7) is preferably small so that the friction with the heat insulating material (7) is reduced to a predetermined value.

  The propulsion device (35, 36) generates a propulsive force by a linear motor. At this time, since the measurement unit (10) travels using wheels, the propulsion device (35, 36) is less likely to be caught by the heat insulating material (7), and can move smoothly in the heat insulating material (7). .

  The tank inspection device according to the present invention further comprises a tunnel (19) for isolating the passage where the measuring unit (50) travels from the heat insulating material (7). At this time, the measurement unit (50) is preferable in that it can move smoothly in the heat insulating layer without being disturbed by the heat insulating material (7).

  The tank inspection apparatus according to the present invention further includes a sensor inspection exchange port (13) for connecting a passage through which the measurement units (10) and (50) pass and a door (12) formed on the outer tank plate. According to such a sensor inspection / exchange port, the measurement units (10) and (50) can be extracted outside the heat insulating layer.

  The measurement unit (50) preferably includes a camera (70) that captures an image of the inner tank plate (3, 4, 16).

  The tank (1) according to the present invention includes an inner tank plate (3, 4, 16) that forms a storage tank for storing liquid, and an inner tank plate (3, 4, 16) an outer tank plate formed in a gap with the measurement unit, a measurement unit (10) (50) arranged on the heat insulating layer and flaw-detecting the inner tank plate (3, 4, 16), and a measurement unit (10) (50). It is preferable to include a propulsion device (35, 36) (65, 66) that travels in the heat insulating layer. According to such a tank (1), cracks generated in the inner tank plates (3, 4, 16) can be easily detected without taking the heat insulating material (7) and the liquid from the tank (1). .

  The tank (1) according to the present invention further comprises a tunnel (19) for isolating the passage in which the measuring unit (50) travels from the heat insulating material (7). Such a tank (1) is preferable in that the measurement unit (50) can move smoothly in the heat insulating layer without being disturbed by the heat insulating material (7).

  The tank (1) according to the present invention further includes a sensor inspection exchange port (13) for connecting a passage through which the measurement units (10) and (50) pass and a door (12) formed on the outer tank plate. Such a tank (1) is preferable in that the measurement unit (10) (50) can be extracted outside the heat insulating layer.

  The tank inspection method according to the present invention is a tank inspection method for flaw detection of the inner tank plates (3, 4, 16) of the tank (1) further provided with a sensor inspection exchange port (13), and the measurement unit (10) ( 50) and a step of replacing the measurement unit (10) (50) with another measurement unit (10) (50) through the sensor inspection / exchange port (13). preferable.

  According to the tank inspection device and the tank inspection method of the present invention, it is possible to facilitate the flaw detection inspection of a tank having a heat insulating material.

  An embodiment of a tank inspection device according to the present invention will be described with reference to the drawings. The tank inspection device is used when inspecting the tank 1 storing LNG, as shown in FIG. The tank 1 includes an inner tank side plate 3, an inner tank annular plate 4, and an outer tank side plate not shown in FIG. The inner tank annular plate 4 is formed of a stainless steel plate and forms a disk. The inner tank side plate 3 is formed of a stainless steel plate and forms a cylinder. The inner tank side plate 3 is further fixed by welding one end of a cylinder to the vertically upper surface of the inner tank annular plate 4. That is, the inner tank side plate 3 and the inner tank annular plate 4 form a storage tank that stores LNG.

  The outer tank side plate is formed of a stainless steel plate and forms a cylinder. The outer tank side plate is further fixed to the ground so that the inner tank side plate 3 and the inner tank annular plate 4 are disposed inside. In the gap between the outer tank side plate and the inner tank side plate 3, a heat insulating layer in which the heat insulating material is disposed is formed.

  The tank inspection apparatus according to the present invention includes a measurement unit 10, a rail 11, a door 12, and a sensor inspection / exchange port 13. The rail 11 is disposed along a welded portion between the inner tank side plate 3 and the inner tank annular plate 4, and defines a path through which the measurement unit 10 travels. The rail 11 is not electrically connected to the inner tank side plate 3 constituting the tank 1 but is electrically connected to a device disposed outside the tank 1 via an electric wire. The door 12 is formed at the same height as the passage where the measurement unit 10 of the outer tank side plate travels. The sensor inspection / exchange port 13 is a tunnel having a diameter larger than that of the measurement unit 10, and connects the door 12 and a passage where the measurement unit 10 travels.

  FIG. 2 shows a heat insulating material disposed outside the inner tank side plate 3. The heat insulating material is formed of pearlite 6 and glass wool 7. The glass wool 7 is formed by forming glass fibers into a plate shape, and is disposed in contact with the surface of the inner tank side plate 3 facing the outer tank side plate. The pearlite 6 is formed by solidifying grains formed from glassy rock, and is disposed between the glass wool 7 and the outer tank side plate.

  FIG. 2 further shows a welded portion where the inner tank side plate 3 is joined to the inner tank annular plate 4. The end face of the inner tank side plate 3 is fixed on the surface of the inner tank annular plate 4. A fillet 16 formed by welding is formed at a corner formed by the inner tank side plate 3 and the inner tank annular plate 4. For this reason, the inner tank annular plate 4 is formed of a portion inside the welded portion and a portion outside the welded portion. A portion inside the welded portion of the inner tank annular plate 4 is in contact with the LNG stored in the tank 1. A portion outside the welded portion of the inner tank annular plate 4 is in contact with the glass wool 7.

  The tank 1 further includes a bottom cooler 5. The bottom cooler 5 is made of concrete and is fixed on the ground. The inner tank annular plate 4 is fixed on the bottom cooler 5. That is, the bottom cooler 5 is disposed between the ground and the inner tank annular plate 4.

  FIG. 2 further shows the measurement unit 10. The surface of the measurement unit 10 is formed from a surface facing the inner tank side plate 3, a surface facing the inner tank annular plate 4, and a surface in contact with the glass wool 7. In the measurement unit 10, the cross section cut by a plane perpendicular to the extending direction of the rail 11 on the surface in contact with the glass wool 7 forms an arc, and the surface in contact with the glass wool 7 is not angular and is gentle. The surface of the measurement unit 10 that contacts the glass wool 7 has a small surface roughness so that the friction with the glass wool 7 is reduced to a predetermined value.

As shown in FIG. 3, the measurement unit 10 is formed of a head portion 21 and a main body portion 22. The head portion 21 is formed in a wedge shape having one end joined to the main body portion 22 and gradually becoming thinner toward the other end. The main body portion 22 forms a columnar shape with the extending direction of the rail 11 as an axis. Further, the joint portion between the head portion 21 and the main body portion 22 is not angular and is gentle, and the measurement unit 10 forms a so-called streamline type. That is, the measurement unit 10 has a shape in which a so-called warhead-shaped warhead is divided into four equal parts by two planes passing through the central axis. For this reason, when the measurement unit 10 travels with the glass wool 7 being spread out, the measurement unit 10 can travel smoothly because the glass wool 7 can be easily pushed away from a shape with a square surface (for example, a column).
Note that the measurement unit 10 can adopt a shape different from such a shape. The shape is such that the resistance to travel away from the glass wool 7 does not become extremely large, and a shape that is easily caught on the glass wool 7 as exemplified by the protrusion is not formed. As the shape, a so-called wedge shape is exemplified.

  As shown in FIG. 4, the measurement unit 10 includes a board computer 31, an oscillator 32, an amplifier 33, a piezoelectric element 34, an inverter 35, a linear motor 36, a tank 37, a pump 38, and a power source 39. The board computer 31 is an information processing device including a CPU, an input / output device, and a storage device, and controls the oscillator 32, the inverter 35, the pump 38, and the power source 39. The oscillator 32 is controlled by the board computer 31 and generates an electric signal indicating the frequency of the ultrasonic wave oscillated from the piezoelectric element 34.

  The amplifier 33 amplifies the electric signal generated by the oscillator 32 and generates an electric signal applied to the piezoelectric element 34. The amplifier 33 further amplifies the electric signal transmitted from the piezoelectric element 34 and outputs an electric signal indicating the reflected wave detected by the piezoelectric element 34 to the board computer 31. The piezoelectric element 34 is made of a material that is distorted when a voltage is applied and generates a voltage when an external force is applied. The piezoelectric element 34 is disposed at the bottom of the measurement unit 10 so that ultrasonic waves can be oscillated on the inner tank annular plate 4. The piezoelectric element 34 oscillates an ultrasonic wave based on the electric signal output from the amplifier 33 and outputs an electric signal indicating a reflected wave reflected from the inner tank annular plate 4 to the amplifier 33. Note that the piezoelectric element 34 can also be disposed at a position other than the bottom of the measurement unit 10. For example, the piezoelectric element 34 is disposed in a portion of the measurement unit 10 facing the inner tank side plate 3 when the inner tank side plate 3 is flawed. The piezoelectric element 34 is disposed in a portion of the measurement unit 10 that faces the fillet 16 when the fillet 16 is flawed.

  The inverter 35 is controlled by the board computer 31 and outputs an electrical signal to the linear motor 36. The linear motor 36 is formed of a coil and generates a moving magnetic field by an electric signal output from the inverter 35 to generate a propulsive force or a braking force of the measurement unit 10.

  The tank 37 stores a contact medium. Examples of the contact medium include water, oil, grease, and glycerin. The pump 38 supplies a contact medium from the tank 37 between the piezoelectric element 34 and the inner tank annular plate 4. At this time, the contact medium enters between the piezoelectric element 34 and the inner tank annular plate 4, and makes it easy for the ultrasonic wave oscillated from the piezoelectric element 34 to propagate to the inner tank annular plate 4.

  The power source 39 is a rechargeable battery, and supplies power to the board computer 31, the oscillator 32, the amplifier 33, the piezoelectric element 34, the inverter 35, the linear motor 36, the tank 37, and the pump 38. The power supply 39 further charges the electric wave oscillated from the rail 11 by converting it into electric power.

  The embodiment of the tank inspection method according to the present invention is a method for flaw detection in the inner tank annular plate 4 of the tank 1 using the tank inspection apparatus according to the present invention. And an operation for inspecting and exchanging the measurement unit 10.

  The operation of flaw-detecting the inner tank annular plate 4 is periodically and periodically repeated. First, an operator who uses the tank inspection apparatus according to the present invention controls the measurement unit 10 by applying a voltage to the rail 11 to detect a crack generated in the inner tank annular plate 4. At this time, the measurement unit 10 charges power converted from radio waves oscillated by the voltage applied to the rail 11, and is controlled by radio waves oscillated by the voltage applied to the rail 11 to use the power. Works.

  That is, the measurement unit 10 travels along a path defined by the rail 11 and stops at the examination site. After stopping, the measurement unit 10 supplies a contact medium between the piezoelectric element 34 and the inner tank annular plate 4 at the inspection site, and oscillates the inner tank annular plate 4 using the piezoelectric element 34. When the ultrasonic wave enters the inner tank annular plate 4, it is reflected by a crack generated in the inner tank annular plate 4. The measurement unit 10 detects the reflected wave of the ultrasonic wave, records information about the reflected wave, and outputs the information to the outside via the rail 11.

  The operator inputs the information output via the rail 11 to the personal computer, analyzes the reflected wave, and determines whether or not the inner tank annular plate 4 is cracked. When a personal computer detects a crack, it analyzes the reflected wave to further calculate the location of the crack and the size of the crack.

  As shown in FIG. 5, the measurement unit 10 is guided by a rail and travels along a corner formed by the inner tank side plate 3 and the inner tank annular plate 4. At this time, the glass wool 7 is pushed by the head portion 21 of the measurement unit 10 and the fiber is elastically deformed, and the gap between the glass wool 7 and the inner tank side plate 3 is widened, and the gap between the glass wool 7 and the inner tank annular plate 4 is increased. spread. The measurement unit 10 travels through the gap. After the measurement unit 10 passes, the glass wool 7 is elastically deformed and returns to the state before the measurement unit 10 passes. The measurement unit 10 has a small surface roughness in contact with the glass wool 7. For this reason, when the measurement unit 10 travels with the glass wool 7 spread out, the measurement unit 10 can travel smoothly with little friction with the glass wool 7. Furthermore, the measurement unit 10 has a gentle surface with no contact with the glass wool 7. For this reason, when the measurement unit 10 travels while spreading the glass wool 7, the surface is not easily caught by the glass wool 7 and can travel smoothly.

  In the operation of inspecting and exchanging the measurement unit 10, first, the measurement unit 10 is caused to travel along the path defined by the rail 11 and stopped at the intersection with the sensor inspection exchange port 13. The operator opens the door 12 and takes out the measuring unit 10 out of the tank 1 through the sensor inspection / exchange port 13. The measuring unit 10 is inspected for normal operation after removal. When the measurement unit 10 does not operate normally, it is repaired or replaced with a measurement unit that operates normally. The measuring unit 10 operating normally is filled in the tank 37 with the contact medium and inserted into the passage defined by the rail 11 via the sensor inspection / exchange port 13. The measurement unit 10 inserted in the passage is used again for the operation of flaw-detecting the inner tank annular plate 4.

  According to such a tank inspection method, cracks generated in the inner tank annular plate 4 can be easily detected without removing the heat insulating material from the tank 1 and without extracting LNG from the tank 1.

  FIG. 6 shows another embodiment of the tank inspection apparatus according to the present invention. In the tank inspection apparatus, the tank 1 in the above-described embodiment further includes a tunnel. That is, the tank 1 includes a measurement unit 50, a rail 11, a door 12, a sensor inspection / exchange port 13, and a tunnel 19. The tunnel 19 is disposed along a welded portion between the inner tank side plate 3 and the inner tank annular plate 4, and defines a passage through which the measurement unit 50 travels. The rail 11 is disposed inside the tunnel 19 of the inner tank side plate 3. The rail 11 is not electrically connected to the inner tank side plate 3 constituting the tank 1 but is electrically connected to a device disposed outside the tank 1 via an electric wire. The door 12 is formed at the same height as the passage where the measurement unit 50 of the outer tank side plate travels. The sensor inspection / exchange port 13 is a tunnel having a diameter larger than that of the measurement unit 50, and connects the door 12 and the tunnel 19 in which the measurement unit 50 travels.

  FIG. 7 shows a welded portion where the inner tank side plate 3 is joined to the inner tank annular plate 4. The heat insulating material disposed on the outer side of the inner tank side plate 3 is formed of pearlite 6 and glass wool 7. The glass wool 7 is formed by forming glass fibers into a plate shape, and is disposed in contact with the surface of the inner tank side plate 3 facing the outer tank side plate. The pearlite 6 is formed by solidifying grains formed from glassy rock, and is disposed between the glass wool 7 and the outer tank side plate.

  The end face of the inner tank side plate 3 is fixed on the surface of the inner tank annular plate 4. A fillet 16 formed by welding is formed at a corner formed by the inner tank side plate 3 and the inner tank annular plate 4. For this reason, the inner tank annular plate 4 is formed of a portion inside the welded portion and a portion outside the welded portion. A portion inside the welded portion of the inner tank annular plate 4 is in contact with the LNG stored in the tank 1. A portion outside the welded portion of the inner tank annular plate 4 is in contact with the glass wool 7.

  The tank 1 further includes a bottom cooler 5. The bottom cooler 5 is made of concrete and is fixed on the ground. The inner tank annular plate 4 is fixed on the bottom cooler. That is, the bottom cooler 5 is disposed between the ground and the inner tank annular plate 4.

  FIG. 7 further shows a tunnel 19. The tunnel 19 is formed of a lower end portion of the inner tank side plate 3, a portion outside the welded portion of the inner tank annular plate 4, and the wall 18. The wall 18 separates the passage and the heat insulating tank so that the pearlite 7 and the glass wool 7 do not leak into the passage where the measurement unit 50 travels.

  As shown in FIG. 8, the measurement unit 50 includes a board computer 61, an oscillator 62, an amplifier 63, a piezoelectric element 64, an inverter 65, a linear motor 66, a tank 67, a pump 68, a power supply 69, and a camera 70. ing. The board computer 61 is an information processing device including a CPU, an input / output device, and a storage device, and controls the oscillator 62, the inverter 65, the pump 68, the power source 69, and the camera 70. The oscillator 62 is controlled by the board computer 61 and generates an electric signal indicating the frequency of the ultrasonic wave oscillated from the piezoelectric element 64.

  The amplifier 63 amplifies the electric signal generated by the oscillator 62 and generates an electric signal applied to the piezoelectric element 64. The amplifier 63 further amplifies the electrical signal transmitted from the piezoelectric element 64 and outputs an electrical signal indicating the reflected wave detected by the piezoelectric element 64 to the board computer 61. The piezoelectric element 64 is made of a material that is distorted when a voltage is applied and generates a voltage when an external force is applied. The piezoelectric element 64 is disposed at the bottom of the measurement unit 50 so that an ultrasonic wave can be oscillated on the inner tank annular plate 4. The piezoelectric element 64 oscillates an ultrasonic wave based on the electric signal output from the amplifier 63 and outputs an electric signal indicating a reflected wave reflected from the inner tank annular plate 4 to the amplifier 63.

  The inverter 65 is controlled by the board computer 61 and outputs an electrical signal to the linear motor 66. The linear motor 66 is formed of a coil, generates a moving magnetic field by an electric signal output from the inverter 65, and generates a propulsive force or a braking force of the measuring unit 50.

  The tank 67 stores a contact medium. The pump 68 supplies a contact medium from the tank 67 between the piezoelectric element 64 and the inner tank annular plate 4. At this time, the contact medium enters between the piezoelectric element 64 and the inner tank annular plate 4, and makes it easy for the ultrasonic wave oscillated from the piezoelectric element 64 to propagate to the inner tank annular plate 4.

  The power source 69 is a rechargeable battery, and supplies power to the board computer 61, the oscillator 62, the amplifier 63, the piezoelectric element 64, the inverter 65, the linear motor 66, the tank 67, the pump 68, and the camera 70. The power source 69 further charges the electric wave oscillated from the rail 11 by converting it into electric power.

  The camera 70 is controlled by the board computer 61, takes images of the inner tank side plate 3, the inner tank annular plate 4 and the fillet 16 in the vicinity of the measurement unit 50, and outputs an electrical signal indicating the image to the board computer 61. To do.

  Another embodiment of the tank inspection method according to the present invention is a method for flaw detection in the inner tank annular plate 4 of the tank 1 using such a tank inspection apparatus. And an operation for inspecting and exchanging the measurement unit 50.

  The operation of flaw-detecting the inner tank annular plate 4 is periodically and periodically repeated. First, an operator who uses the tank inspection device controls the measurement unit 50 by applying a voltage to the rail 11 to detect a crack generated in the inner tank annular plate 4. At this time, the measurement unit 50 is charged with electric power converted from radio waves oscillated by the voltage applied to the rail 11, and is controlled by radio waves oscillated by the voltage applied to the rail 11, and uses the electric power. Works.

  That is, the measurement unit 50 travels along the path defined by the tunnel 19 and stops at the examination site. After stopping, the measurement unit 50 supplies a contact medium between the piezoelectric element 64 and the inner tank annular plate 4 at the inspection site, and oscillates ultrasonic waves on the inner tank annular plate 4 using the piezoelectric element 64. When the ultrasonic wave enters the inner tank annular plate 4, it is reflected by a crack generated in the inner tank annular plate 4. The measurement unit 50 detects the reflected wave of the ultrasonic wave, records information on the reflected wave, and outputs the information to the outside via the rail 11. The measurement unit 50 further takes images of the inner tank side plate 3, the inner tank annular plate 4 and the fillet 16 in the vicinity of the measurement unit 50 using the camera 70, and outputs the images to the outside via the rail 11. To do.

  The operator inputs the information output via the rail 11 to the personal computer, analyzes the reflected wave, and determines whether or not the inner tank annular plate 4 is cracked. When a personal computer detects a crack, it analyzes the reflected wave to further calculate the location of the crack and the size of the crack. The operator further performs a visual inspection based on the images of the inner tank side plate 3, the inner tank annular plate 4, and the fillet 16 captured by the measurement unit 50.

  In the operation of inspecting and exchanging the measurement unit 50, first, the measurement unit 50 travels through the tunnel 19 and stops at the intersection with the sensor inspection exchange port 13. The operator opens the door 12 and takes out the measuring unit 50 out of the tank 1 through the sensor inspection / exchange port 13. The measuring unit 50 is inspected for normal operation after removal. When the measurement unit 50 does not operate normally, it is repaired or replaced with a measurement unit that operates normally. The measuring unit 50 that operates normally is filled in the tank 67 with the contact medium and inserted into the tunnel 19 through the sensor inspection / exchange port 13. The measurement unit 50 inserted into the tunnel 19 is used again for the operation of flaw-detecting the inner tank annular plate 4.

  According to such a tank inspection method, it is possible to easily detect a crack generated in the inner tank annular plate 4 without removing the heat insulating material from the tank 1 and without extracting LNG from the tank 1.

FIG. 1 is an exploded perspective view showing an embodiment of a tank inspection apparatus according to the present invention. FIG. 2 is a cross-sectional view showing a welded portion where the inner tank side plate is joined to the inner tank annular plate and the measurement unit. FIG. 3 is a cross-sectional view showing the measurement unit. FIG. 4 is a cross-sectional view showing the measurement unit, and is a block diagram showing the measurement unit. FIG. 5 is an exploded perspective view showing the measurement unit. FIG. 6 is an exploded perspective view showing another embodiment of the tank inspection apparatus according to the present invention. FIG. 7 is a cross-sectional view showing a welded portion where the inner tank side plate is joined to the inner tank annular plate and the measurement unit. FIG. 8 is a cross-sectional view showing the measurement unit, and is a block diagram showing the measurement unit. FIG. 9 is a cross-sectional view showing a known tank. FIG. 10 is a cross-sectional view showing a welded portion where an inner tank side plate of a known tank is joined to an inner tank annular plate.

Explanation of symbols

1: tank 2: outer tank side plate 3: inner tank side plate 4: inner tank annular plate 6: perlite 7: glass wool 10: measurement unit 11: rail 12: door 13: sensor inspection inspection port 16: fillet 21: head portion 22 : Main part 31: Board computer 32: Oscillator 33: Amplifier 34: Piezoelectric element 35: Inverter 36: Linear motor 37: Tank 38: Pump 39: Power supply

Claims (12)

An inner tank plate forming a storage tank for storing liquid;
It is a tank provided with an outer tank plate that forms a heat insulating layer in which the heat insulating material is disposed in a gap with the inner tank plate, and is a tank inspection device used when flaws generated in the inner tank plate are flawed,
A sensor unit arranged in the heat insulating layer to detect the inner tank plate;
A tank inspection device comprising: a propulsion device that causes the sensor unit to travel in the heat insulating layer. In claim 1,
The measurement unit is
A contact medium tank for storing the contact medium;
A tank inspection apparatus comprising: a pump that supplies the contact medium to a gap between the inner tank plate and the sensor that oscillates the ultrasonic wave. In either claim 1 or claim 2,
The sensor unit is a tank inspection device with a sharp top. In any one of Claims 1-3,
The sensor unit has a gentle surface in contact with the heat insulating material. Tank inspection device. In any one of Claims 1-4,
The propulsion device is a tank inspection device that generates a propulsion force by a linear motor. In either claim 1 or claim 2,
A tank inspection apparatus further comprising a tunnel for isolating a passage in which the measurement unit travels from the heat insulating material. In any one of Claims 1-6,
A tank inspection apparatus further comprising a sensor inspection exchange port for connecting a passage through which the measurement unit passes and a door formed on the outer tank plate. In either claim 6 or claim 7,
The said measurement unit is equipped with the camera which image | photographs the image of the said inner tank board Tank inspection apparatus. An inner tank plate forming a storage tank for storing liquid;
An outer tank plate that forms a heat insulating layer in which a heat insulating material is disposed in a gap with the inner tank plate;
A sensor unit arranged in the heat insulating layer to detect the inner tank plate;
And a propulsion device that causes the sensor unit to travel in the heat insulating layer. In claim 9,
A tank further comprising a tunnel for isolating a passage through which the measurement unit travels from the heat insulating material. In either claim 9 or claim 10,
A tank further comprising a sensor inspection exchange port for connecting a passage through which the measurement unit passes and a door formed on the outer tank plate. A tank inspection method for flaw detection of the inner tank plate of the tank according to claim 11,
Flaw detection using the measurement unit;
A tank inspection method comprising: replacing the measurement unit with another measurement unit via the sensor inspection exchange port.

Images