JPS6042409B2 - Underground tank leak detection device - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a device for detecting leakage of stored liquid from a tank body through a pipe when a storage tank for liquefied gas, petroleum, etc. is an underground tank. In particular, it relates to an underground tank leak detection device that detects leaks by collecting and analyzing the diffused gas at multiple positions in the circumferential direction and height direction during the process of gas diffusion of leaked liquid along the concrete structure. It is an invention.

Conventional technology There are various types of tanks that store liquids such as liquefied gas and petroleum, but in recent years, tanks have been destroyed due to earthquakes, etc., resulting in leakage of stored liquid and resulting fires. Semi-underground type and underground type underground tanks (hereinafter referred to as underground tanks) have been attracting attention due to pollution problems such as fire spreading to adjacent tanks and destruction of landscapes in rural areas.
Various new technologies have been improved, developed and proposed for this purpose, and are gradually being adopted, but there are still many unresolved problems.

Problems to be Solved by the Invention In the case of underground tanks, when the above-mentioned pollution problem occurs, appropriate countermeasures are taken above ground, but with underground tanks of this type, the main body and frame are located in the ground, so no countermeasures can be taken. There are some drawbacks that are difficult to strengthen.

That is, as shown in Fig. 1, the tank body 1 of the underground tank
If a crack occurs due to an earthquake, etc., and cracks also occur in the concrete frame 2 on the outside, the stored liquid 4, etc. may penetrate into the ground 3 and cause groundwater to leak, since there is no countermeasure as described above. It has the disadvantage of being contaminated.

Conventionally, the only way to deal with this problem was to increase the thickness of the steel lining of the tank body 1, which had the disadvantage of resulting in extremely high costs.

The purpose of this invention is to solve the problem of leakage of liquid stored in an underground tank based on the above-mentioned conventional technology as a technical problem to be solved, and to detect the leakage by detecting gasification of the leaked liquid outside the concrete frame and take countermeasures. It is an object of the present invention to provide an excellent underground tank leakage detection method and a device for direct use thereof, which will benefit the field of tank utilization in the energy industry. Means/Action for Solving the Problems In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned object and the gist of the above-mentioned claims, is to solve the above-mentioned problems. Although cracks are assumed to occur as an unavoidable assumption, analysis equipment installed on the ground captures the liquid stored in the tank leaking outward from the concrete structure, partially gasifying it, and dispersing along the outside of the concrete structure. Therefore, it is possible to analyze and find out from which height of the tank the leak is coming from, through a number of holes drilled in the bottom of the detection vibrator, which is wound multiple times in the height direction along the outside of the concrete frame. In addition, technical measures have been taken to prevent underground water from seeping out by providing an impermeable membrane between the concrete frame and the ground.

Embodiment Next, an embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

A continuous underground wall 5 is constructed in the ground 3, and a sheet 6 as an impermeable membrane such as vinyl is stretched on the inner surface of the continuous underground wall 5 and the internal ground 3 in an open-bottomed manner. As shown in FIGS. 3 and 4, a ring-shaped vibrator 7 is provided with a large number of small holes 8 at its bottom.
8... are bored in the impermeable sheet 6 at predetermined intervals in the height direction so as to be appropriately attached to the impermeable sheet 6 in a ring shape, and concrete is poured inside of the impermeable sheet 6 to form the concrete frame 2. After that, a predetermined tank body 1 is constructed inside the concrete frame 2.

A communication vibrator 9 is connected to a predetermined portion of the ring-shaped vibrator 7 and extended, and is connected through a weir 10 to a gas chromatograph (not shown) of a gas analysis mechanism 11 as a detection mechanism disposed near the tank. .

As mentioned above, in the constructed underground tank, liquefied petroleum gas, petroleum, etc. 4 are received and discharged to the tank body 1 and put into operation, and when it is operated over time, the concrete frame 2 is exposed to the As shown in the figure, when a crack 12 occurs and a crack 13 also occurs in the tank body 1 due to an earthquake or the like, the stored liquid 4 such as liquefied gas or petroleum is damaged by the crack 13 and
It begins to leak outward from the crack 12.

As the leaked stored liquid 4 flows out along the concrete frame 2, a part of it loses its pressure balance, gasifies, and tries to spread.

Therefore, a part of the diffused gas is sucked through the small holes 8, 8, . leakage of the stored liquid 4 is immediately detected.

Then, by installing the vibrators 7 at predetermined intervals in the height direction, it is possible to approximately detect in which position in the height direction the leakage has occurred. In addition, the sheet 6 of the impermeable membrane body may partially break during the above-mentioned leakage process, causing underground water to infiltrate. However, since the gas diffuses upward and the water infiltrates downward,
There is no risk of groundwater infiltrating into the small holes 8, 8, etc.

After leakage from the tank is detected, liquefied petroleum gas, petroleum, etc. 4 may be discharged from the emergency tank body 1, and the tank body 1 may be repaired and maintained at the detected location.

In the above-mentioned embodiment, the vibrators 7 are individually arranged around the concrete frame 2, but the vibrators may be surrounded in a spiral shape as a detection means. More than the effects of the invention, according to the invention, there is a tank bottom plate in the ground, and
In an underground tank with a concrete frame at the bottom,
During the process in which the stored liquid leaking from the tank body and the concrete frame gasifies and diffuses along the concrete frame, the gas is captured through a hole drilled in the bottom of a vibrator that is wrapped vertically on the outside of the concrete frame. Gas leakage, that is, leakage of stored liquid, can be detected immediately by collecting the gas and performing gas analysis. Therefore, through gas diffusion and rapid detection of gas analysis, leakage of stored liquid can be detected at an extremely early stage. This has the excellent effect of making it possible to take emergency measures before tank cracks become large.

It is especially useful for underground and semi-underground tanks, where unlike open above-ground tanks, it is impossible to see the tank side plates and concrete frame, making maintenance and inspection difficult, and where repairs are often delayed and lead to serious problems. It is effective as a means of coping.

In addition, by installing a detection vibrator with multiple holes in the bottom and perforated in the side of the concrete frame in a spiral shape in multiple stages in the height direction, it is possible to detect separated gas from the stored liquid leaking from the tank as described above. is sucked into the vibrator through the hole in the detection vibrator, and is detected by a separate gas detection mechanism, so it is possible to detect from which part in the height direction the gas has leaked.Furthermore, the tank itself has a special complicated device. It has the advantage of being extremely simple in structure and requires no maintenance.

Furthermore, since a water-impermeable membrane is interposed between the detection vibrator and the ground, groundwater in the ground does not infiltrate into the detection vibrator, resulting in more accurate detection. .

Furthermore, in terms of design, it is possible to detect leakage of stored liquid from the tank body at an early stage by providing a detection vibrator on the inner surface of the concrete frame instead of on the outer surface of the concrete frame.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of an underground tank structure, Fig. 2 and the following are explanatory views of one embodiment of the invention of this application, Fig. 2 is a longitudinal sectional view, Fig. 3 is a partially enlarged sectional view of Fig. 2, FIG. 4 is a partial perspective view of the detection vibrator. 3... Ground, 2... Concrete frame, 1... Tank body, 4... Liquid, 8...
... Hole, 7... Detection vibe, 11...
- Gas detection mechanism, 6... impermeable membrane.

Claims (1)

[Claims] 1. In a leakage detection device attached to an underground tank that has a tank body installed in the ground through a concrete frame, a detection pipe with a number of holes drilled at the bottom on the outside surface of the concrete frame is wound around multiple times. surrounding the gas detection pipe, and connecting the detection pipe to a gas detection mechanism on the ground.
A leak detection device for an underground tank, further comprising an impermeable membrane interposed between the outside of the detection pipe and the ground.