JP2006023274A - Leakage inspection device for liquid storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leakage inspection device for a liquid storage tank capable of detecting minute fluctuations in the liquid face level caused by leakage of a liquid. <P>SOLUTION: In this leakage inspection device C having a float 4 floating on a liquid face, a wire 5 for suspending the float at its lower end, and a swing balancer 3 with a midway fixed to a pivotal shaft 2, arranged swingably around an axis of the pivotal shaft 2, with one end fixed to the wire 5, and with the other end attached with a weight 7, a displacement of the other end in the swing balancer 3 is measured electrically by a sensor mechanism 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a leak inspection apparatus for inspecting the presence or absence of liquid leakage from a liquid storage tank installed in a gas station, a factory, or the like. In addition, in this application, "leakage" shall mean both the outflow of the storage liquid from a liquid storage tank, and the inflow of rain water, groundwater, etc. to a liquid storage tank.

  Since liquid storage tanks buried underground are used for a long time, holes or cracks occur due to corrosion of the partition wall, or the liquid stored inside flows out to the outside for other reasons, or Rainwater, groundwater, etc. may flow from the outside.

  Conventionally, an apparatus described in Patent Document 1 is known as an apparatus for inspecting the presence or absence of such leakage. In the leakage inspection apparatus described in Patent Document 1, a float that floats on a liquid surface and a swing balancer that can swing around a pivot are connected by a wire, and an indicator needle is provided on the pivot. That is, in the leak inspection apparatus described in Patent Document 1, when the float moves up and down due to liquid leakage, the pivot supporting the swing balancer rotates, and the indicator needle swings accordingly. Is recorded on the recording board and monitored to check for leaks.

  However, in the leakage inspection apparatus described in Patent Document 1, when the float moves up and down (liquid level fluctuation) due to liquid leakage is minute, the indicator needle also swings so that it is difficult to inspect for leakage. There was a problem. That is, as a measure of the presence or absence of leakage according to the US standard, it is determined that there is leakage when the change in liquid volume is 0.38 L / h or more, but when this is converted into fluctuations in the liquid level, for example, a tank of 10 kL In such a case, it is as small as about 0.05 mm, and it is difficult for the leak inspection apparatus described in Patent Document 1 to detect such a minute fluctuation in the liquid level.

  In addition, in the periodic inspection for inspecting the presence or absence of leakage in the liquid storage tank, in order to shorten the inspection time, the gas phase part and the liquid phase part are inspected simultaneously by applying pressure (positive pressure or negative pressure) to the gas phase part. Although the leak inspection apparatus described in Patent Document 1 does not have an airtight structure, pressure cannot be applied to the gas phase part in a state where a leak inspection apparatus that performs a leak inspection of the liquid phase part is attached. Therefore, the inspection of the gas phase portion and the liquid phase portion has to be performed separately, and there is a problem that the inspection time becomes long.

Furthermore, when pressure (positive pressure or negative pressure) is applied to the gas phase portion for inspection of the gas phase portion, the internal pressure of the liquid storage tank changes, and as a result, the liquid in the liquid storage tank and the liquid storage tank itself Since it expands or contracts, the zero point of the leakage inspection apparatus adjusted in the atmospheric pressure state (no pressure state) is shifted. Therefore, for the zero point readjustment, it is necessary to perform the troublesome work of measuring the zero point deviation while applying pressure, then returning to the atmospheric pressure state and adjusting for the zero point deviation. Met.
No. 2-33238

  SUMMARY OF THE INVENTION A first problem to be solved by the present invention is to provide a liquid storage tank leakage inspection device capable of detecting minute fluctuations in the liquid level due to liquid leakage.

  The second problem is to provide a liquid storage tank leakage inspection apparatus capable of simultaneously performing a leakage inspection of a gas phase portion and a liquid phase portion of the liquid storage tank.

  A third problem is to provide a liquid storage tank leakage inspection device that can easily perform zero point adjustment from the outside.

  The present invention includes a float that floats on a liquid surface, a wire that supports a float at a lower end, a midway fixed to a pivot, and a swingable arrangement around the axis of the pivot, and one end of the wire In a leak check apparatus for a liquid storage tank having a swing balancer that is fixed and has a weight attached to the other end, a sensor mechanism that measures the displacement of the other end of the swing balancer is provided.

  The sensor mechanism includes a light emitter, a reflector fixed to the other end of the swing balancer, and a light receiver. Light reflected from the light emitter is reflected by the reflector and returned. The incoming light can be received by the light receiver, and the displacement of the other end of the swing balancer can be electrically measured by changing the light receiving position.

  In addition, by making the length from the pivot to the sensor mechanism installation position in the swing balancer longer than the length from the pivot to the wire fixing position, the displacement of the other end of the swing balancer is amplified more than the displacement of the wire attachment position. Can do.

  Furthermore, the present invention provides a float that floats on the liquid surface, a wire that suspends the float at the lower end, a midway fixed to the pivot, and swingable around the axis of the pivot, and one end of the wire In a leak inspection apparatus for a liquid storage tank having a swing balancer fixed to a wire and having a weight attached to the other end, a sensor mechanism for electrically measuring the amount of rotation of the pivot is provided.

  In the present invention, it is preferable that a portion communicating with the liquid storage tank has an airtight structure, and it is preferable to provide a zero point adjusting mechanism that moves the pivot up and down so as to be operable from the outside.

  Furthermore, in this invention, it is preferable to provide the display part which displays and monitors the data acquired from the sensor part or obtained by the calculation in the vicinity of the sensor mechanism. The installation position of the display unit can be changed as appropriate.

  In addition, in the present invention, it is preferable to make the swing balancer visible from the outside by providing a transparent or translucent window or the like on the outer surface of the apparatus.

  In the present invention, the displacement of the swing balancer that swings with the vertical movement of the float that floats on the liquid surface, or the amount of rotation of the pivot that serves as the rotation axis of the swing balancer is measured by the sensor mechanism. Variations in the liquid level can be detected, and a highly accurate leak test can be performed.

  In addition, since the portion communicating with the liquid storage tank has an airtight structure, it is possible to apply pressure to the gas phase portion of the liquid storage tank with the leakage inspection device attached, so that the gas phase portion and the liquid phase portion leak. The inspection can be performed at the same time, and the inspection time can be shortened.

  Furthermore, the zero point adjustment mechanism that moves the pivot axis of the swing balancer up and down can be operated from the outside, so that the zero point adjustment can be easily performed from the outside, and the work time for zero point adjustment can be shortened. Can do.

  In addition, by providing a display unit in the vicinity of the sensor mechanism, it is possible to check the status of zero point adjustment, liquid level fluctuation and the like at the work place, so that workability can be improved.

  Further, by making the swing balancer inside the apparatus visible from the outside, zero point adjustment can be performed while confirming the position and posture of the swing balancer, and zero point adjustment can be performed more easily.

  Hereinafter, embodiments of the present invention will be described by way of examples in which the present invention is applied as a leak inspection device for an underground tank of a gas station.

  FIG. 1 is a schematic configuration diagram of a gas station to which a leakage inspection apparatus of the present invention is applied. An underground tank A is embedded in the gas station, and a manhole B is provided above it. A main body case 1 of the leakage inspection apparatus C is installed above the manhole B, and the main body case 1 and the underground tank A are connected by a communication pipe D.

  FIG. 2 is a front view showing the main part of the first embodiment of the leakage inspection apparatus C.

  A pivot 2 is supported on the main body case 1 of the leakage inspection apparatus C so as to be rotatable and vertically movable, and the middle of the swing balancer 3 is fixed to the pivot 2. A midway of a wire 5 for hanging the float 4 is fixed to one end of the swing balancer 3 by a fixing mechanism 6, and a weight 7 is attached to the other end. A float 4 floating on the liquid level in the underground tank A is connected to the lower end of the wire 5, and when the float 4 is floating, the swing balancer 3 is kept in an equilibrium state. The relationship between the buoyancy and the gravity of the weight 7 is adjusted. The upper end of the wire 5 is wound around the rotary roll 8.

  FIG. 3 is a cross-sectional view showing a fixing mechanism 6 that fixes the wire 5 to the swing balancer 3.

  In the fixing mechanism 6, a hole penetrating the swing balancer 3 is provided, and a clamping mechanism including a cylindrical body 6a and an insertable insertion body 6b in the cylindrical body 6a is provided therebetween. The cylindrical body 6a and the insertion body 6b are urged away from each other by a spring 6c, and wire insertion holes 6d and 6d 'are provided in the overlapping portions, respectively, and the wire 5 is inserted through these wire insertion holes 6d and 6d'. . Since the cylindrical body 6a and the insertion body 6b are urged away from each other, the wire insertion holes 6d and 6d 'are urged in alternate directions to fix the wire 5.

  When such a fixing mechanism 6 is employed, the initial liquid level in the underground tank A can be quickly released by pressing both end surfaces of the cylinder 6a and the insert 6b, thereby quickly releasing the fixation between the wire 5 and the swing balancer 3. The wire 5 can be easily raised and lowered according to the level.

  Returning to FIG. 2, a sensor mechanism 9 that electrically measures the vertical displacement of the other end of the swing balancer 3 is provided on the other end side (the attachment side of the weight 7) of the swing balancer 3. The length from the pivot 2 to the sensor mechanism 9 installation position in the swing balancer 3 is longer than the length from the pivot 2 to the wire fixing position (fixing mechanism 6). Thereby, the displacement of the installation position of the sensor mechanism 9 becomes larger than the displacement of the wire fixing position.

  The sensor mechanism 9 includes a light emitter 9a, a light receiver 9b, a reflector 9c, and a calculation unit 9d. Light emitted obliquely from the light emitter 9a is reflected by the reflector 9c and received by the light receiver 9b. Yes. The light receiver 9b has a certain size, and a light reception signal indicating the light reception position is transmitted to the arithmetic unit 9d via the signal line 10. The calculation unit 9d acquires data of the light receiving position in the light receiving body 9b based on the light receiving signal from the light receiving body 9b.

  Here, the light emitting element 9a and the light receiving element 9b are fixed to the main body case 1, the reflecting plate 9c is fixed to the other end of the swing balancer 3, and the light emitter 9a of the sensor mechanism 9 emits light in an oblique direction. Therefore, when the other end of the swing balancer 3 is displaced, the light receiving position in the light receiving element 9b changes. The calculation unit 9d detects the displacement amount of the other end of the swing balancer 3, that is, the fluctuation of the liquid level, based on the change of the light receiving position in the light receiving element 9b, and records, outputs or displays it on the display unit 9e. The display unit 9e can be built in the main body case 1 and can be provided at a plurality of locations.

  In the present embodiment, by using the sensor mechanism 9 as described above, the fluctuation of the liquid level can be detected in units of 0.005 mm.

  Further, in the present embodiment, in the main body case 1 communicating with the underground tank A, the area within the thick line in FIG. This makes it possible to apply pressure (positive pressure or negative pressure) to the gas phase portion of the underground tank A with the leakage inspection device C attached. In a region having an airtight structure, a transparent glass 11 is disposed between the light emitter 9a, the light receiver 9b, and the reflector 9c of the sensor mechanism 9 to ensure translucency. In addition, the front side of the region having the airtight structure is formed of a transparent or translucent member such as an acrylic plate so that the inside of the main body case 1 can be visually observed.

  Further, in the present embodiment, the adjusting screw 12 is provided as a zero point adjusting mechanism for adjusting the zero point of the leakage inspection apparatus C by moving the pivot 2 up and down. The adjustment screw 12 is attached to the main body case 1 through an airtight seal material 13 so as to be movable up and down (retracted), and can be operated from outside the main body case 1. The adjustment screw 12 moves up and down by the operation, and moves the pivot 2 up and down via the adjustment unit 14.

  When the pivot 2 moves up and down, one end side of the swing balancer 3 is fixed to the wire 5, so that the swing balancer 3 tilts with that as a fulcrum. As a result, the other end of the swing balancer 3 moves up and down, and the distance between the reflector 9c of the sensor mechanism 9 fixed to the other end, the light emitter 9a, and the light receiver 9b changes. Thus, by operating the adjustment screw 12 from the outside, the distance between the reflecting plate 9c of the sensor mechanism 9 and the light emitter 9a and the light receiver 9b can be adjusted to adjust the zero point.

  Further, in this embodiment, in order to confirm the zero point adjustment and the transition state of the liquid level data, a display unit 9e for displaying and monitoring the output value from the sensor unit and the data obtained by the calculation is provided in the vicinity of the sensor unit. Therefore, workability can be improved.

  The zero point adjustment is performed while confirming the data displayed on the display unit 9e as described above. However, when the swing balancer 3 is greatly tilted and is outside the measurement range of the sensor mechanism 9, only an error is displayed on the display unit 9e. Therefore, it is not clear in which direction the swing balancer 3 should be tilted by the adjusting screw 12. On the other hand, in the present embodiment, as described above, the front side of the region of the main body case 1 having the airtight structure is formed of a transparent or translucent member so that the inside of the main body case 1 can be visually observed. 3 can be adjusted while visually confirming the position and orientation of the position 3, and even if the swing balancer 3 is largely inclined outside the measurement range of the sensor mechanism 9, the zero point adjustment operation can be easily performed.

  In the embodiment, the entire front side of the region having the airtight structure of the main body case 1 is formed of a transparent or translucent member. However, a part thereof is formed of a transparent or translucent member, and at least the swing balancer 3 is provided. It can also be made visible from the outside.

  4 to 6 show other embodiments of a sensor mechanism that electrically measures the displacement of the other end of the swing balancer.

  The sensor mechanism 15 shown in FIG. 4 is a differential transformer type displacement sensor including an iron core 15a fixed to the other end of the swing balancer 3, a transformer 15b fixed to the main body case 1, and an arithmetic unit 15c. . In this sensor mechanism 15, when the iron core 15 a moves in the vertical direction as the liquid level changes, an induced voltage is generated in the secondary coil of the transformer 15 b, and the swing balancer is calculated from the magnitude of the induced voltage in the calculation unit 15 c. 3 is calculated and detected, that is, the fluctuation of the liquid level.

  In the embodiment shown in FIG. 4, in the main body case 1 communicating with the underground tank A, the region within the thick line in FIG. 4 has an airtight structure. In addition, the iron core 15a of the sensor mechanism 15 and the boundary part of the area | region made into airtight structure are sealed by the airtight sealing material 16 so that the iron core 15a can move up and down. In addition, the front side of the region having the airtight structure is formed of a transparent or translucent member such as an acrylic plate so that the inside of the main body case 1 can be visually observed.

  Also in the embodiment shown in FIG. 4, the adjusting screw 12 is provided as a zero point adjusting mechanism, as in the embodiment of FIG. 2. By operating the adjusting screw 12 from the outside, the vertical position of the iron core 15a and the transformer 15b of the sensor mechanism 15 can be adjusted to adjust the zero point.

  Furthermore, in order to confirm the status of zero point adjustment and liquid level data transition, a display unit 15d is provided in the vicinity of the sensor unit for monitoring the output value from the sensor unit and data obtained by calculation. The workability can be improved. In addition, since the front side of the region having the airtight structure is formed of a transparent or translucent member, even if the swing balancer 3 is largely inclined outside the measurement range of the sensor mechanism 15, the position of the swing balancer 3 The zero point adjustment operation can be easily performed while visually confirming the posture.

  The sensor mechanism 17 shown in FIG. 5 is a magnetostrictive displacement sensor including a magnet 17a fixed to the other end of the swing balancer 3, a magnetostrictive wire 17b and a detection unit 17c fixed to the main body case 1, and a calculation unit 17d. It is. In this sensor mechanism 17, a torsional distortion ultrasonic vibration pulse is generated in the magnetostrictive wire 17 b where the magnet 17 a is located by the interaction between the magnetic field generated from the magnet 17 a and the pulse current supplied to the magnetostrictive wire 17 b. Then, the time until the ultrasonic vibration pulse is received by the detection unit 17c is electrically detected, and the position of the magnet 17a is calculated from the time by the calculation unit 17d, thereby the other end of the swing balancer 3 is calculated. The displacement amount, that is, the fluctuation of the liquid level is calculated and detected.

  In the embodiment shown in FIG. 5, in the main body case 1 communicating with the underground tank A, the region within the thick line in FIG. 5 has an airtight structure. Note that the boundary between the magnetostrictive wire 17 b of the sensor mechanism 17 and the region having the airtight structure is sealed by the airtight seal material 16. In addition, the front side of the region having the airtight structure is formed of a transparent or translucent member such as an acrylic plate so that the inside of the main body case 1 can be visually observed.

  In the embodiment shown in FIG. 5 as well, the adjusting screw 12 is provided as a zero point adjusting mechanism, as in the embodiment of FIG. By operating the adjusting screw 12 from the outside, the vertical position of the magnet 17a and the magnetostrictive wire 17b of the sensor mechanism 17 can be adjusted to adjust the zero point.

  Furthermore, in order to check the zero point adjustment and the state of liquid level data transition, a display unit 17e is provided in the vicinity of the sensor unit for monitoring the output value from the sensor unit and data obtained by calculation. The workability can be improved. In addition, since the front side of the region having the airtight structure is formed of a transparent or translucent member, even if the swing balancer 3 is largely inclined outside the measurement range of the sensor mechanism 17, the position of the swing balancer 3 The zero point adjustment operation can be easily performed while visually confirming the posture.

  The sensor mechanism 18 shown in FIG. 6 includes a magnet 18a fixed to the other end of the swing balancer 3, a magnetic sensor 18b fixed to the main body case 1, and an arithmetic unit 18c. In this sensor mechanism 18, the magnetic force generated from the magnet 18 a is detected by the magnetic sensor 18 b, and the displacement of the other end of the swing balancer 3, that is, the fluctuation of the liquid level is detected by the calculation unit 18 c from the magnitude of the magnetic force. To do.

  In the embodiment shown in FIG. 6, in the main body case 1 communicating with the underground tank A, the region within the thick line in FIG. 6 has an airtight structure. In the airtight structure, a nonmagnetic plate 19 such as transparent glass is disposed between the magnet 18a of the sensor mechanism 18 and the magnetic force sensor 18b so as not to impede the transmission of magnetic force from the magnet 18a. Yes. In addition, the front side of the region having the airtight structure is formed of a transparent or translucent member such as an acrylic plate so that the inside of the main body case 1 can be visually observed.

  In the embodiment shown in FIG. 6 as well, the adjusting screw 12 is provided as a zero point adjusting mechanism, as in the embodiment of FIG. By operating this adjusting screw 12 from the outside, the distance between the magnet 18a of the sensor mechanism 18 and the magnetic force sensor 18b can be adjusted to adjust the zero point.

  Furthermore, in order to confirm the status of zero point adjustment and liquid level data transition, the display unit 18d for displaying and monitoring the output value from the sensor unit and the data obtained by calculation is provided in the vicinity of the sensor unit. The workability can be improved. In addition, since the front side of the region having the airtight structure is formed of a transparent or translucent member, even if the swing balancer 3 is greatly inclined outside the measurement range of the sensor mechanism 18, the position of the swing balancer 3 The zero point adjustment operation can be easily performed while visually confirming the posture.

  FIG. 7 is a front view showing a main part of a second embodiment of the leakage inspection apparatus C. In FIG. 7, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the fluctuation of the liquid level is detected by electrically measuring the rotation amount of the pivot 2 that is the rotation axis of the swing balancer 3.

  In this embodiment, the rotary encoder 20 is used as a sensor mechanism for electrically measuring the rotation amount of the pivot 2. In the rotary encoder 20, the sensor unit 20 a transmits a pulse signal corresponding to the rotation amount of the pivot 2, and the calculation unit 20 b calculates the rotation amount of the pivot 2 from the pulse signal, whereby the other end of the swing balancer 3 is calculated. Displacement amount, that is, fluctuation of the liquid level is calculated and detected.

  In the present embodiment, the entire main body case 1 communicating with the underground tank A has an airtight structure. This makes it possible to apply pressure (positive pressure or negative pressure) to the gas phase portion of the underground tank A with the leakage inspection device C attached. In addition, the front side of the region having the airtight structure is formed of a transparent or translucent member such as an acrylic plate so that the inside of the main body case 1 can be visually observed.

  Further, in the present embodiment, as in the first embodiment, the adjusting screw 12 is provided as a zero point adjusting mechanism for adjusting the zero point of the leakage inspection apparatus C by moving the pivot 2 up and down. When the pivot 2 is moved up and down by the operation of the adjusting screw 12, the swing balancer 3 tilts with the one end side of the swing balancer 3 fixed to the wire 5 as a fulcrum. Accordingly, the pivot 2 of the swing balancer 3 rotates. Thus, by operating the adjustment screw 12 from the outside, the rotation amount of the pivot 2 can be adjusted to adjust the zero point.

  In addition, in order to confirm the status of zero point adjustment and liquid level data transition, a display unit 20c for displaying and monitoring the output value from the sensor unit and data obtained by calculation is provided in the vicinity of the sensor unit. Therefore, workability can be improved. Further, since the front side of the region having the airtight structure is formed of a transparent or semi-transparent member, even if the swing balancer 3 is largely inclined outside the measurement range of the sensor mechanism (rotary encoder 20), the swing balancer 3 The zero point adjustment operation can be easily performed while visually confirming the position and posture of the lens.

  The present invention can be applied as a leakage inspection apparatus that inspects leakage of liquid from any liquid storage tank installed in a gas station, a factory, or the like.

It is a schematic block diagram of the gas station to which the leakage inspection apparatus of this invention is applied. It is a front view which shows the principal part of 1st Example of a leak test | inspection apparatus. It is sectional drawing which shows the fixing mechanism which fixes a wire to a swing balancer. Another embodiment of the sensor mechanism for measuring the displacement of the other end of the swing balancer is shown. Another embodiment of the sensor mechanism for measuring the displacement of the other end of the swing balancer is shown. Another embodiment of the sensor mechanism for measuring the displacement of the other end of the swing balancer is shown. It is a front view which shows the principal part of 2nd Example of a leak test | inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body case 2 Pivot 3 Swing balancer 4 Float 5 Wire 6 Fixing mechanism 6a Tubing body 6b Insertion body 6c Spring 6d, 6d 'Wire insertion hole 7 Weight 8 Rotating roll 9 Sensor mechanism 9a Light emitter 9b Light receiver 9c Reflector 9d Calculation part 9e Display unit 10 Signal line 11 Transparent glass 12 Adjustment screw (Zero point adjustment mechanism)
DESCRIPTION OF SYMBOLS 13 Airtight sealing material 14 Adjustment part 15 Sensor mechanism 15a Iron core 15b Transformer 15c Calculation part 15d Display part 16 Airtight sealing material 17 Sensor mechanism 17a Magnet 17b Magnetostrictive wire 17c Detection part 17d Calculation part 17e Display part 18 Sensor mechanism 18a Magnet 18b Magnetic sensor 18c arithmetic unit 18d display unit 19 non-magnetic plate 20 rotary encoder 20a sensor unit 20b arithmetic unit 20c display unit A underground tank B manhole C leakage inspection device D communication pipe

Claims (8)

A float floating on the liquid surface;
A wire for hanging a float at the lower end;
Leakage inspection apparatus for a liquid storage tank having a swing balancer that is fixed in the middle of the pivot and swingably arranged around the axis of the pivot, and having one end fixed to the wire and a weight attached to the other end In
A liquid storage tank leak inspection apparatus comprising a sensor mechanism for measuring a displacement of the other end of the swing balancer.   The sensor mechanism includes a light emitter, a reflector fixed to the other end of the swing balancer, and a light receiver. Light reflected obliquely from the light emitter is reflected by the reflector and returned. The liquid storage tank leakage inspection device according to claim 1, wherein the received light is received by the light receiving body, and the displacement of the other end of the swing balancer is electrically measured by a change in the light receiving position.   The leakage inspection device for a liquid storage tank according to claim 1 or 2, wherein a length from the pivot axis to the sensor mechanism installation position in the swing balancer is longer than a length from the pivot axis to the wire fixing position. A float floating on the liquid surface;
A wire for hanging a float at the lower end;
Leakage inspection apparatus for a liquid storage tank having a swing balancer that is fixed in the middle of the pivot and swingably arranged around the axis of the pivot, and having one end fixed to the wire and a weight attached to the other end In
A liquid storage tank leakage inspection apparatus, comprising a sensor mechanism for electrically measuring the amount of rotation of the pivot.   The leak inspection device for a liquid storage tank according to any one of claims 1 to 4, wherein a portion communicating with the liquid storage tank has an airtight structure.   6. The liquid storage tank leakage inspection device according to claim 1, wherein a zero point adjusting mechanism for vertically moving the pivot is provided so as to be operable from the outside.   The liquid storage tank leakage inspection device according to claim 6, wherein the swing balancer is visible from the outside.   The liquid storage tank leakage inspection device according to claim 1, wherein the sensor mechanism includes a display unit that displays and monitors data acquired from the sensor unit or obtained by calculation.

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