JPH0617146B2 - Underground tank with leak detection mechanism - Google Patents

Description

The present invention relates to an underground tank having a leak detection mechanism.

[Conventional technology]

Oil tanks such as gasoline that are buried underground in conventional oil facilities such as gas stations are made of steel according to the provisions of the Fire Service Law, but such tanks are generally susceptible to corrosion, and the area immediately below the oil injection hole is injected. There was a defect that holes were easily opened due to hydraulic pressure (erosion).

Further, even if the outer periphery of the tank is rust-proofed by a bituminous rust-proof layer such as coal tar, the oil that has permeated from the ground dissolves the rust-proof layer and the outer circumference of the tank is easily corroded.

Further, in order to know the fact of the perforation of the tank buried underground, for example, an inert gas is injected into the tank so that the tank has a predetermined pressure, and the leak is detected from the time change of this pressure. However, in general, the tank has a large capacity and a large amount of gas is introduced into the tank, so that the work is troublesome and the detection error is large.

[Object of the Invention]

An object of the present invention is to obtain an underground tank having a leak detection mechanism that eliminates the above-mentioned drawbacks.

[Structure of Invention]

An underground tank having a leak detection mechanism of the present invention is an inner tank for containing a liquid, a thin net sheet wound around the outer circumference of the inner tank, and a cloth is tightly wound around the outer circumference of the thin net sheet, and a resin is applied and cured. The outer tank formed as described above, a conduit opening into a minute gap between the inner and outer tanks, a mechanism for introducing liquid into the gap through the conduit, and a change in the level of the liquid in the conduit is detected. It is characterized by comprising a mechanism.

Further, the underground tank having the leak detection mechanism of the present invention has a mechanism for detecting the level change of the liquid in the inner tank.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIGS. 1 and 2, for example, a 0.2 mm thick Saran wrap (trade name) is provided on the outer circumference of a cylindrical steel inner tank 1 having an inner diameter of about 2 m, a length of about 6 m and a thickness of about 6 mm. 2.) Sheets of polyvinylidene chloride mesh etc.) are intermittently or densely wound, and a glass fiber cloth is tightly wound on the sheet, and unsaturated polyester is applied on the sheet for natural curing. In this way, the unsaturated polyester permeates the glass fibers and spontaneously cures them to form the outer tank 3, and the polyvinylidene chloride sheet portion forms the gap 2 with a gap of about 0.2 mm. become.

It should be noted that the finely hatched portion on the outer periphery of the inner tank 1 shown in FIGS. 1 and 2 indicates the sheet of the mesh or the like, and a desired gap 2 communicating with each other is formed in the mesh sheet. In FIGS. 2 and 3, these net sheets and the gap 2 are shown separately from each other for convenience.

Further, a steel conduit 4 having an outer diameter of about 80 mm and a thickness of about 6 mm, which extends from the upper part of the outer tank 3 in an airtight manner and opens into the gap 2, is provided, and water is introduced into the gap 2 through the conduit 4. And the like, and a mechanism for detecting the level of the liquid in the conduit 4, for example, a viewing window (not shown) is provided.

Reference numeral 5 denotes a tank socket having an oil injection hole, a ventilation hole, etc. provided through the upper and inner tanks 1 and 3 so as to penetrate them.

Since the underground tank having the leakage detection mechanism of the present invention has the above-described structure, if the inner tank 1 leaks, the liquid in the conduit 4 and the gap 2 flows into the inner tank 1. However, since the level of the liquid in the conduit 4 decreases, the leakage of the inner tank 1 can be detected by detecting this.

Even if there is a leak in the outer tank 3, the level of the liquid in the conduit 4 is similarly reduced, so that it is unclear whether the leak has occurred in the inner tank 1 or the outer tank 3.

Therefore, in another embodiment of the present invention, at this time, whether or not the level of the liquid in the inner tank 1 rises can be simultaneously detected. By doing so, it is possible to more reliably detect whether the inner tank 1 or the outer tank 3 is leaking.

(Effects of the Invention) As described above, according to the underground tank having the leakage detection mechanism of the present invention, not only the leakage of the tank can be accurately detected easily, but also a minute gap is uniformly formed between the double tanks. However, the present invention can easily and surely achieve the above-mentioned object by an extremely simple means of winding a mesh sheet. Further, conventionally, a small gap is formed on the outer periphery of the inner tank. It was a technically extremely difficult task to form the outer tank via the, but in the present invention, the outer tank is formed by closely winding a cloth around the outer periphery of the thin mesh sheet and applying a resin to the cloth. Therefore, there is a great advantage that the outer tank can be formed extremely easily and reliably.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an underground tank having a leak detection mechanism of the present invention, and FIG. 2 is a vertical sectional side view. 1 ... Inner tank, 2 ... Gap, 3 ... Outer tank, 4
…… Conduit, 5 …… Tank socket.

Claims (2)

[Claims] 1. An inner tank for containing a liquid, a thin net sheet wound around the outer circumference of the inner tank, and an outer tank formed by tightly winding a cloth around the outer circumference of the thin net sheet and applying and curing a resin. , A conduit opening into a minute gap between the inner and outer tanks, a mechanism for introducing a liquid into the gap through the conduit, and a mechanism for detecting a level change of the liquid in the conduit. An underground tank with a leak detection mechanism. 2. An underground tank having a leak detection mechanism according to claim 1, including a mechanism for detecting a level change of the liquid in the inner tank.