JP6732310B2 - Underground buried reinforced plastic lining double shell tank - Google Patents

Description

The present invention relates to an underground buried type reinforced plastic lining double-shell tank, and more specifically, for example, a tank inner shell made of steel or the like (hereinafter referred to as a tank for storing dangerous materials buried underground) And a tank outer shell (hereinafter simply referred to as “outer shell”) including a reinforced plastic layer coated on the inner shell . and it relates to a liquid storage tank underground type, in particular, it relates to the tank make it possible to reliably detect the damage of the outer shell ing from reinforced plastic layer.

The law that revises part of the regulations on the regulation of dangerous goods and the regulation that revises part of the regulations on the regulation of dangerous materials were revised and enforced, and dangerous goods by a reinforced plastic lining double-shell tank buried underground Can be stored.

It reinforced plastic lining double-shelled tank (hereinafter, simply referred to as "double-shelled tanks.") And has a tank body provided with a fiber-reinforced plastic (FRP) Tona Ru shell on the outside of the steel of the inner shell It is a tank. The tank body may be damaged by cracks or the like due to an external force at the time of backfilling of the earth and sand when the tank is buried, or an external force due to an earthquake or uneven settlement of the ground. Since such damage may cause a serious accident such as breakage of the tank, it is necessary to detect the damage early and make necessary repairs.

As a means for detecting damage to the tank body, the fiber is formed so that a gap is formed between the inner shell and the outer shell in the upper portion of the tank and the portion (liquid phase portion L) other than the flange portion (vapor phase portion G). A tank body is provided with a reinforced plastic layer (FRP layer) (Patent Documents 1 and 3), a liquid level gauge connected to the gap is provided at the upper part of the tank, and liquid is injected into the gap to monitor changes in the liquid level. A structure is proposed in Patent Document 2, for example.

In the above structure, it is necessary to monitor the liquid level of the liquid in the gap and the liquid level of the liquid in the tank to determine whether the inner shell or the outer shell of the tank is damaged (Patent Document 2). However, the volume of the inner shell 1 is so large that it is difficult to detect a slight leak.

On the other hand, as shown in FIGS. 3 and 4, the detection tube 51 that communicates with the bottom surface of the gap 2 between the inner shell 1 and the outer shell 3 from the upper portion of the tank body 4 is inserted, and the bottom portion of the detection tube 51 is inserted. Is provided with a liquid sensor 52 capable of detecting both the content leaking from the inner shell 1 and the groundwater flowing in from the outer shell 3, and a monitor 7 for processing the output of the liquid sensor is provided at an appropriate location. By arranging them, a structure is provided in which a leak detection device 5 for detecting which of the inner shell 1 and the outer shell 3 is damaged is provided (Patent Document 4).

However, with the above structure, damage to the outer shell 3 cannot be detected when the tank is installed in a place where there is no groundwater or when the groundwater level drops. Therefore, in order to confirm that there is no damage to the outer shell 3 which is the reinforced plastic layer of the double shell tank, the gap 2 is regularly (or once every three years by default) pressurized or depressurized to change the pressure. By looking at it, the outer shell 3 is checked for leaks. This is defined because damage to the outer shell 3 cannot be detected in a place where there is no groundwater.

Japanese Patent No. 4332075 Japanese Patent Publication No. 6-17146 JP, 10-114392, A JP, 2011-025987, A

The detection tube 51 communicating with the gap 2 formed between the inner shell 1 and the outer shell 3 of the tank body is inserted from the upper part to the bottom surface of the tank body 4 and leaks from the inner shell 1 to the bottom part of the detection tube 51. The structure provided with the liquid sensor 52 for detecting the contents and the means for detecting the leakage of the outer shell 3 by pressurizing or depressurizing the gap 2 defined once every three years and observing the pressure change. If used together, regardless of the presence or absence of groundwater, when damage such as cracks occurs in the inner shell 1 and the outer shell 3, including whether the damage occurred in the inner shell 1 or the outer shell 3, Can be detected.

However, the work of manually pressurizing or depressurizing the gap 2 and checking the pressure change is troublesome and requires experience, and there is a risk of inadvertent detection error. In the worst case, the leakage test of the outer shell once every three years will leave it undetected for three years after the damage occurs, during which time an earthquake will occur and the tank will be destroyed. In view of the possibility that this may occur, it is desirable to be able to detect outer shell damage more frequently, and preferably continuously.

The present invention relates to a double shell tank equipped with means capable of always detecting damage to the inner shell, and a double shell tank capable of automatically detecting damage to the outer shell always or at a set time interval. The challenge is to get a tank.

The present invention relates to a double shell tank equipped with a leak detection device 5 capable of constantly detecting damage to the inner shell 1 by pressurizing or depressurizing the gap 2 at a time interval set by the controller 8 to pressurize and depressurize. The above problem is solved by automatically detecting the pressure fluctuation at the time or after finishing the pressurization/decompression and comparing it with the threshold value set in the controller 8.

That is, the pressurizing/depressurizing device 10 for pressurizing or depressurizing the gap 2 between the inner shell 1 and the outer shell 3, the controller 8 for operating the pressurizing/depressurizing device at set time intervals, and during the pressurizing/depressurizing process A pressure sensor 16 for detecting the pressure fluctuation in the gap 2 after the pressurization and depressurization is provided. The controller 8 is provided with a setter that sets the operation timing of the pressurizing/depressurizing device 10 and a setter that sets the threshold value of the pressure fluctuation in the gap 2, and controls the pressure fluctuation detected by the pressure sensor 16. The presence or absence of damage is judged by comparing with a threshold value. Then, when the liquid sensor 52 of the detection tube 51 does not detect the contents, it is assumed that the outer shell 3 is damaged.

According to the present invention, in a reinforced plastic lined double shell tank, when damage such as cracks occurs in the tank body, it becomes possible to immediately detect whether the inner shell or the outer shell is damaged, and it is buried underground. There is an effect that it is possible to reliably detect the damage of the damaged tank.

1 is a sectional side view of a tank showing a first embodiment and a block diagram of a control system. Second Embodiment A sectional side view of a tank and a block diagram of a control system showing a second embodiment. Sectional side view of tank showing conventional structure Vertical cross-sectional view of the tank of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to a horizontal cylindrical double-shell tank as an example. 1 and 2 showing an embodiment of the present invention, a tank body 4 is a double-shell tank having an inner shell 1 made of steel and an outer shell 3 made of a fiber reinforced plastic layer, and a tank upper part 41 A gap 2 is formed between the inner shell 1 and the outer shell 3 of the liquid phase portion L other than the gas phase portion G. Although the gap 2 is illustrated wider than the thickness of the inner shell 1 and the outer shell 3, the actual size is usually 1 mm or less. Manholes 42 and 43 for installing pipes in the tank and for checking and repairing the inside of the tank are provided in the tank upper portion 41.

The leak detection device 5 for detecting the leakage of the tank content liquid from the inner shell 1 includes a detection pipe 51 penetrating the upper part of the tank and communicating with the gap 2 at the bottom face of the tank, and a tank content liquid at the bottom part of the detection pipe. It is composed of a liquid sensor 52 for detecting and a monitor 7 for processing a detection signal of the liquid sensor 52 drawn out through the detection tube 51. When the inner shell 1 is damaged such that the content liquid leaks out, the content liquid leaks into the gap 2, flows down to the bottom of the tank, and is detected by the liquid sensor 52, so that the inner shell 1 is not cracked or otherwise damaged. Can be detected.

The double shell tank of the present invention further includes an outer shell inspection device 6 (6a, 6b) in addition to the leak detection device 5 having the above structure. The outer shell inspection device 6 pressurizes or depressurizes the gap 2 at time intervals set by the controller 8 and automatically confirms pressure fluctuations during pressurization and depressurization or after completion of pressurization and depressurization. Then, the damage of the outer shell 3 is detected.

In the outer shell inspection devices 6a and 6b shown in FIGS. 1 and 2, 11 is an inert gas cylinder, 12 is a pressure reducing valve, 13 is a manual valve, 14 is a solenoid valve which is opened and closed at a time interval set in the controller 8, 15 Is a safety valve, 16 is a pressure sensor, and 17 shown only in FIG. 1 is a thermometer.

FIG. 1 shows an embodiment in which the gap 2 is pressurized and the outer shell is inspected for damage. When the solenoid valve 14 is opened, an inert gas is passed through the detection tube 51 to form a gap between the inner shell 1 and the outer shell 3. 2 is supplied. After the solenoid valve 14 is opened and the pressure detected by the pressure sensor 16 is increased to approximately 20 kpa (kilopascal), the solenoid valve 14 is closed and the pressure sensor 16 adjusts the pressure fluctuation while performing pressure correction based on the temperature data of the thermometer 17. Monitor. Whether or not the tank is damaged is constantly checked by comparing the detected pressure fluctuation pattern with the normal pressure pattern registered in advance in the controller 8.

FIG. 2 shows an embodiment in the case of inspecting the outer shell for damage under reduced pressure, in which 18 is an ejector and 19 is a second solenoid valve which is opened and closed simultaneously with the solenoid valve 14. In the case of decompression, the solenoid valves 14 and 19 are opened to guide the gas of the inert gas cylinder 11 to the ejector 18, and the air in the gap 2 is blown to reduce the pressure to 20 kpa. Then, by comparing the pressure fluctuation after closing the solenoid valves 14 and 19 with the fluctuation pattern set in the controller 8, it is always confirmed whether or not the tank is damaged. In the case of depressurization, the temperature of the air in the gap 2 can be regarded as constant while the pressure fluctuation is being measured, so there is no need to make corrections due to temperature changes, and therefore no thermometer is provided.

1 Inner shell 2 Gap 3 Outer shell 5 Leak detector 6 Outer shell inspection device 7 Monitor 8 Controller 10 Pressure regulator 51 Detector tube 52 Liquid sensor

Claims (2)

In double-shelled tanks underground type with an outer shell air ing from reinforced plastic layer over a possible distribution gap between the outer surface of the inner shell, the gap at the tank bottom through the top of the tank A leak detection device equipped with a detection pipe communicating with the detection pipe and a liquid sensor for detecting the liquid content in the tank at the bottom of the detection pipe, and damage to the outer shell when the liquid sensor does not detect the content liquid or groundwater. And an outer shell inspection device for detecting
The outer shell inspection device includes a pressurizing/depressurizing device that pressurizes or depressurizes the inside of the gap, a controller that operates the pressurizing/depressurizing device at set time intervals, and a pressure in the gap during or after the operation. A pressure sensor for detecting fluctuations, wherein the controller detects damage to the outer shell by comparing a preset pattern of pressure fluctuations with a pattern of pressure fluctuations detected by the pressure sensor; Reinforced plastic lined double shell tank. In double-shelled tanks underground type with an outer shell air ing from reinforced plastic layer over a possible distribution gap between the outer surface of the inner shell, the gap at the tank bottom through the top of the tank A leak detection device having a detection pipe communicating with the detection pipe and a liquid sensor for detecting the tank content liquid at the bottom of the detection pipe, and an outer shell inspection device for detecting damage to the outer shell,
The outer shell inspection device includes a pressurizing/depressurizing device that pressurizes or depressurizes the inside of the gap, a controller that operates the pressurizing/depressurizing device at set time intervals, and a pressure in the gap during or after the operation. A pressure sensor for detecting fluctuations is provided, and the controller detects damage by comparing a preset pattern of pressure fluctuations with a pattern of pressure fluctuations detected by the pressure sensor. An underground buried reinforced plastic lined double shell tank that claims damage to the outer shell when the sensor is not detecting the contents.

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