JP2020200068A - Double shell structure of underground tank with leak detection device - Google Patents

Abstract

To provide a double shell structure of underground tank which has a pressure sensor inside that detect beforehand leakage of gasoline and organic solvent etc.SOLUTION: Of an underground tank of double-shell structure including an inner shell, an outer shell, and a pressure sensor provided in a minute space between the inner shell and the outer shell, when corrosion or pitting corrosion occurs on the inner shell or outer shell, and further the pressure in the minute space deviates from the preset value due to the corrosion holes or pitting holes, the pressure sensor detects this and notifies the administrator of defects of the underground tank.SELECTED DRAWING: Figure 1

Description

In the present invention, a shell having a thickness of several mm is formed inside an existing buried tank with FRP or the like, a minute space is provided between the inner shell and the buried tank, and the minute space is pressurized or depressurized to detect pressure fluctuation. The present invention relates to a double-shell structure of a buried tank, which has a structure for detecting oil leaks such as gasoline and solvent leaks such as organic solvents in advance.

Today, steel underground tanks for oil storage are widely used in gas stations and the like. In addition, the number of solvent tanks for storing organic solvents such as toluene, xylene, and alcohol is increasing with the spread of fuel cell vehicles and the like.

However, such a buried tank may change over time due to long-term use and cause corrosion or pitting corrosion, which causes oil leakage and solvent leakage. Furthermore, once a steel tank is buried, it is difficult to inspect the tank for corrosion and pitting corrosion from the ground.

For this reason, for example, Patent Document 1 proposes a synthetic resin buried tank that does not require advanced processing technology in tank manufacturing, does not require labor for manufacturing, and requires less construction labor. However, once an oil leak such as gasoline or a solvent leak occurs, it has a great impact on the environment such as soil pollution. In particular, when oil leakage or solvent leakage continues for a long period of time, not only soil pollution but also penetration into groundwater and the like becomes a big social problem.

Japanese Unexamined Patent Publication No. 2003-261195

Therefore, in the present invention, the tank buried underground is a buried tank having a double-shell structure, and further, an buried tank equipped with a pressure sensor as a detector for detecting oil leakage and solvent leakage is used to prevent oil leakage and solvent leakage. Fluctuations in pressurization or depressurization of minute spaces that detect pressure changes in the gap between the inner shell and outer shell before they occur, prevent soil contamination, etc., and eliminate adverse effects on the environment such as groundwater contamination. Provided is a double shell structure of a buried tank equipped with a pressure sensor and an alarm to detect the above.

The present invention is a double-shell structure embedded tank provided with an inner shell, an outer shell, and a pressure sensor for detecting the pressure in a minute space between the inner shell and the outer shell in order to solve the above problems. For example, if corrosion or pitting corrosion occurs in the inner shell or outer shell, and the pressure in the minute space deviates from the preset value due to the corrosion hole or pitting corrosion, the pressure sensor detects this and causes a defect in the buried tank. This can be achieved by providing a double shelled buried tank to notify the administrator.

Further, the pressure sensor is a pressure fluctuation detection device, and when the measured value deviates from a preset value, the administrator is notified of the defect of the buried tank.

Further, the detection information by the pressure sensor or the pressure fluctuation detection device is transmitted to an external monitor via a communication line, and the defect of the buried tank is displayed on the monitor.

Further, in order to solve the above problems, the present invention includes a double inner shell, an outer shell, and a pressure sensor (pressure fluctuation detection device) for detecting the pressure in a minute space between the inner shell and the outer shell. If a defect detection program is installed in the control device used for the buried tank of the shell structure, for example, if the inner shell or outer shell is eroded or pitted and the pressure in the minute space deviates from the preset value, follow the above program. The control device transmits the information detected by the pressure sensor or the pressure fluctuation detection device to the administrator's personal computer, and displays the defect of the buried tank on the display of the personal computer.

Further, in order to solve the above problems, the present invention provides a double-shell structure embedded tank provided with an inner shell, an outer shell, and a pressure sensor for detecting the pressure in a minute space between the inner shell and the outer shell. In the control method of the control device used, when the inner shell or the outer shell is eroded or pitted and the pressure in the minute space deviates from a preset value, the control device is the pressure sensor or the pressure fluctuation. The feature is that the information detected by the detection device is transmitted to the administrator's personal computer, and the defect of the buried tank is displayed on the display of the personal computer.

According to the present invention, by using a double-shell structure buried tank equipped with a pressure sensor and a pressure fluctuation detection device, corrosion and pitting corrosion occurring in the buried tank can be known at an early stage, and oil leakage and solvent leakage can be detected. It is possible to prevent soil contamination caused by the above.

It is a figure which shows the example of the buried tank of the double shell structure provided with the pressure sensor of this embodiment. It is a figure explaining the pressure fluctuation detection system including the pressure sensor installed in the buried tank. It is a figure which shows the structure of the personal computer provided in the office. It is a flowchart explaining the initial setting process of the reference pressure of a minute space. It is a flowchart explaining the defect detection process by a pressure sensor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an example of a double-shell structure buried tank provided with the pressure sensor of the present embodiment. In the figure, the buried tank 1 includes, for example, a lubrication pipe 2 for inserting gasoline, a refueling pipe 3 for sucking gasoline from the underground tank 1, a ventilation pipe 4 for ventilating the buried tank 1, and gasoline stored in the buried tank 1. A liquid level gauge 5 for measuring the liquid level of the above is installed. Further, the buried tank 1 is buried at a predetermined depth from the ground surface, and concrete is installed on the buried tank 1.

The lubrication pipe 2 is provided with an lubrication port 7 on the ground surface, and gasoline is lubricated from the lubrication port 7. Further, the oil supply pipe 3 is provided with equipment 8 such as a measuring instrument and a pump on the ground surface, and sucks gasoline from the buried tank 1 to measure the sucked gasoline. Further, the lubrication pipe 2 is provided with a valve 9, and the lubrication pipe 3 is provided with a valve 10. The ventilation pipe 4 is provided with a ventilation port 12 to discharge the gas generated in the buried tank 1.

Further, the buried tank 1 of this example is provided with a pressure detection cylinder 15, and a pressure fluctuation detection device 16 for detecting pressure fluctuations in a minute space, which will be described later, is provided above the pressure detection cylinder 15.

FIG. 2 is an enlarged view of the vicinity of the pressure detection cylinder 15 and the pressure fluctuation detection device 16, and is a diagram for explaining the pressure fluctuation detection system of this example in detail. As shown in the figure, the buried tank 1 is composed of an outer shell 24 made of steel plate and an inner shell 25 made of FRP (fiber reinforced composite material), and a primer for preventing rust is formed on the lower surface of the steel plate (outer shell). Processing 23 is applied. Further, a spacer is interposed between the outer shell 24 and the inner shell 25 to form a constant minute space 26. This minute space 26 is also a pressure detection space between the outer shell 24 and the inner shell 25.

The pressure detection cylinder 15 communicates with the minute space (pressure detection space) 26, and the same pressure as the pressure applied to the minute space 26 is applied to the pressure detection cylinder 15. A pressure inspection nozzle 17 is provided on the upper part of the pressure detection cylinder 15, and is connected to the pressure fluctuation detection device 16 via an on-off valve 18.

The pressure fluctuation detection device 16 is provided with a pressure sensor inside, and detects the pressure fluctuation in the minute space 26. Further, a pressure display meter 19 is provided above the pressure fluctuation detection device 16. The pressure display meter 19 displays the pressure value of the minute space 26 detected by the pressure fluctuation detection device 16, and is mainly used when the initial pressure of the minute space 26 is set.

Further, a pressurizing / depressurizing pump 21 is connected to the pressure fluctuation detecting device 16 via an on-off valve 20. The pressurizing / depressurizing pump 21 is used to set the initial pressure of the minute space 26. For example, the on-off valve 20 is opened, the pressurizing / depressurizing pump 21 is operated, and the initial pressure of the minute space 26 is set while looking at the pressure display meter 19.

The pressure fluctuation detection device 16 detects the internal pressure of the minute space 26 (pressure detection cylinder 15), and when it detects a pressure exceeding a preset range, it notifies the administrator. Therefore, as shown in the figure, a signal line 32 extends from the pressure fluctuation detection device 16 to the personal computer 31 installed in the office 30, and information on the pressure fluctuation in the minute space 26 detected by the pressure fluctuation detection device 16. Is always transmitted to the personal computer 31. Then, when a value exceeding a preset range is detected, the administrator is notified.

The pressure detection cylinder 15 and the pressure fluctuation detection device 16 are installed in the inspection port 22 provided in the upper part of the buried tank 1 as shown in FIG.

FIG. 3 is a diagram showing the configuration of a personal computer 31 provided in the office 30, which is composed of a CPU 33, a ROM 34, a RAM 35, etc., performs the processing of this example according to a program stored in the ROM 34, and records a device 36 as necessary. To access. Further, necessary information is displayed on the display 37, and for example, the pressure data of the minute space 26 input via the signal line 32 is displayed.

The system control of this example is executed according to the program stored in the ROM 34, and as shown in the figure, a recording medium 38 such as a CD-ROM, a flexible disk, or an MO is attached to the media driver arranged in the computer. However, the program may be read out from the recording medium 38 and used.

In the buried tank 1 having the above configuration, the processing operation of this example will be described below.
First, the reference pressure of the minute space 26 is initially set. FIG. 4 is a flowchart illustrating this process. First, the on-off valve 18 is opened, the on-off valve 20 is closed, and the initial pressure of the minute space 26 (pressure detection cylinder 15) is measured by the pressure fluctuation detection device 16 (step (hereinafter, indicated by S) 1). In addition, this work is performed, for example, by an operator entering the inspection port 22, operating the on-off valves 18 and 20, and visually observing the pressure display meter 19.

Then, first, it is determined whether or not the initial pressure of the minute space 26 is equal to or higher than the atmospheric pressure (S2). Here, when the initial value is equal to or higher than the atmospheric pressure (YES in S2), it is determined that the minute space 26 is in a relatively high pressure state, and the range of the initial pressure is set to P1 to P2 (S3). For example, P1 is set to 1000 mmHg and P2 is set to 1200 mmHg. This pressure range is defined as the pressure range of a normal microspace 26 in which no corrosion holes or pitting holes are formed in the buried tank 1.

On the other hand, when the initial value is below atmospheric pressure (S2 is NO), it is determined that the pressure detection space 26 is in a relatively low pressure state, and the reference initial pressure range is set to P3 to P4 (S4). .. That is, in this case, this pressure range is set to the normal range in which no corrosion holes or pitting holes are formed in the buried tank 1. In this way, the reason for setting the two ranges at the time of initial setting is that, for example, the soil temperature differs between summer and winter, and the temperature of oil such as gasoline and organic solvent unloaded from the tank truck also differs depending on the season, so the buried tank This is to consider the shrinkage and expansion phenomena of the steel plate and FRP constituting 1.

Next, in the buried tank 1 set as described above, the defect detection process by the pressure fluctuation detection device 16 will be described. FIG. 5 is a flowchart illustrating this process.
The personal computer 31 installed in the office 30 constantly receives the data from the pressure fluctuation detection device 16 and monitors the pressure information from the pressure fluctuation detection device 16 according to the above-mentioned program (step (hereinafter, in ST). Show) 1). Here, for example, when the initial setting pressure range of this example is set to atmospheric pressure or higher (ST2 is YES), is the detection data from the pressure fluctuation detection device 16 within the initial setting P1 to P2? to decide.

Specifically, first, it is determined whether the detected pressure of the pressure fluctuation detecting device 16 is P1 or less (ST3). Here, if the detection pressure of the pressure fluctuation detection device 16 is not P1 or less (ST3 is NO), it is further determined whether the detection pressure of the pressure fluctuation detection device 16 is P2 or more (ST4). Then, if the detected pressure is not P2 or more (ST4 is NO), it is determined that the minute space 26 is in the normal pressure range, and the pressure monitoring of the minute space 26 is continued (ST1 to ST4).

On the other hand, when it is out of the initial setting range of P1 to P2 (ST3 is YES or ST4 is YES), it is assumed that a corrosion hole or a pitting hole that causes oil leakage or solvent leakage is formed in the minute space 26. Judging, for example, the display 37 on the personal computer 31 is displayed. In addition, an alarm is sounded together with the above display to notify the administrator of the abnormality (ST5).

When the pressure drops below the initial lower limit value P1, for example, corrosion holes and pitting holes are formed in the outer shell 24 and the inner shell 25, and the air in the minute space 26 flows out to the lower limit value or less. This is the case. On the other hand, when the pressure rises above the initial upper limit value P2, corrosion holes and pitting holes are formed in the inner shell 25, oil and organic solvent invade the minute space 26, or corrosion holes are formed in the outer shell 24. This is a case where pitting corrosion holes are formed and groundwater or the like has invaded the minute space 26.

On the other hand, when the default pressure range is set to atmospheric pressure or lower (ST2 is NO), it is determined whether the detection data from the pressure fluctuation detection device 16 is within the default range P3 to P4 (ST5). .. That is, also in this case, first, it is determined whether the detected pressure of the pressure fluctuation detecting device 16 is P3 or less (ST6). Here, if the detection pressure of the pressure fluctuation detection device 16 is not P3 or less (ST6 is NO), it is further determined whether the detection pressure is P4 or more (ST7). Then, if the detected pressure of the pressure fluctuation detection device 16 is not P4 or higher (ST7 is NO), it is determined that the minute space 26 is in the normal pressure range, and the monitoring of the minute space 26 is continued (ST1, ST2, ST6). , ST7).

On the other hand, when it deviates from the initial setting range of P3 to P4 (ST6 is YES or ST7 is YES), it is assumed that corrosion holes and pitting holes that cause oil leakage and solvent leakage are formed in the minute space 26. Upon determination, a display is displayed on the display 37 of the personal computer 31 as described above, an alarm is sounded together with this display, and the administrator is notified of the abnormality (ST8). In this case as well, when the pressure drops below the initial setting lower limit value P3, for example, corrosion holes and pitting holes are formed in the outer shell 24 and the inner shell 25, and the air in the pressure detection space 26 flows out. On the other hand, when the pressure rises above the default upper limit value P4, corrosion holes and pitting holes are formed in the inner shell 25, and oil and organic solvent invade the minute space 26. However, this is a case where corrosion holes and pitting holes are formed in the outer shell 24 and groundwater or the like invades the minute space 26.

When the steel plate or FRP of the buried tank 1 is deteriorated by use, corrosion holes and pitting holes are generated, and gasoline (oil) and an organic solvent infiltrate from the portions. However, as described above, according to this example, the minute space 26 between the inner shell and the outer shell is used as a pressure detection space, and the space pressure of this minute space 26 is constantly monitored by the pressure fluctuation detection device 16 to cause corrosion holes. As soon as a pitting corrosion hole is formed, the pressure fluctuation detection device 16 can detect a pressure abnormality and notify the administrator to prevent soil contamination due to gasoline (oil) leakage or organic solvent leakage. it can.

In the description of the above embodiment, P1 is set to 1000 mmHg and P2 is set to 1200 mmHg as the initial value of the minute space 26, but it can be arbitrarily set including the initial pressure values of P3 and P4. It is not limited to the value.

1 ... Buried tank 2 ... Lubrication pipe 3 ... Lubrication pipe 4 ... Ventilation pipe 5 ... Liquid level gauge 7 ... Lubrication port 8 ... Equipment 9, 10 ... Valve 12・ ・ Vent 15 ・ ・ Pressure detection tube 16 ・ ・ Pressure fluctuation detection device 17 ・ ・ Pressure inspection nozzles 18 and 20 ・ ・ On-off valve 19 ・ ・ Pressure display meter 21 ・ ・ Pressure / depressurization pump 22 ・ ・ Inspection port 23 ・・ Primer processing 24 ・ ・ Outer shell 25 ・ ・ Inner shell 26 ・ ・ Micro space 30 ・ ・ Office 31 ・ ・ Personal computer 32 ・ ・ Signal line 33 ・ ・ CPU
34 ... ROM
35 ... RAM
36 ... Recording device 38 ... Recording medium

Claims (5)

A double-shell structure buried tank equipped with an inner shell, an outer shell, and a pressure sensor for detecting the pressure in a minute space between the inner shell and the outer shell.
When corrosion or pitting corrosion occurs in the inner shell or outer shell, and the pressure in the minute space deviates from a preset value due to the corrosion hole or pitting corrosion, the pressure sensor detects this and causes a defect in the buried tank. Double-shell construction of a buried tank with a pressure sensor characterized by notifying the administrator. The pressure sensor according to claim 1, wherein the pressure sensor is a pressure fluctuation detection device, and notifies the manager of a defect of the buried tank when the measured value deviates from a preset predetermined value. Double shell structure of the buried tank equipped. The pressure according to claim 1 or 2, wherein the information of the pressure sensor or the pressure fluctuation detection device is transmitted to an external monitor via a communication line, and a defect display of the buried tank is performed on the monitor. Double shell structure of buried tank with sensor. A program to be introduced into a control device used for a double-shelled buried tank equipped with an inner shell, an outer shell, and a pressure sensor for detecting the pressure in a minute space between the inner shell and the outer shell. ,
When corrosion or pitting corrosion occurs in the inner shell or outer shell and the pressure in the minute space deviates from a preset value, the control device transmits the information detected by the pressure sensor or the pressure fluctuation detection device to the administrator's personal computer. A defect detection program characterized by transmitting and displaying defects in the buried tank on the display of a personal computer. A control method for a control device used in a double-shell structure buried tank including an inner shell, an outer shell, and a pressure sensor for detecting the pressure in a minute space between the inner shell and the outer shell.
When corrosion or pitting corrosion occurs in the inner shell or outer shell and the pressure in the minute space deviates from a preset value, the control device transmits the information detected by the pressure sensor or the pressure fluctuation detection device to the administrator's personal computer. A control method characterized by transmitting and displaying defects in the buried tank on the display of a personal computer.

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