JPS63218086A - Tank for underground storage of liquid fuel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a liquid fuel storage tank for storing liquid fuel such as gasoline, kerosene, light oil, heavy oil, etc. underground.

(Prior art and problems to be solved by the invention) Conventionally, the first and second types of liquid fuel underground storage devices for storing liquid fuel such as gasoline underground have been approved by the current Fire Service Act. There was a storage device. Figures 5 and 6
The configurations and problems of both storage devices will be explained in order based on the figures.

(First liquid fuel underground storage device) The first storage device shown in Fig. 5 has a concrete wall 1 made of reinforced concrete in the shape of an open square box with a bottom, and its inner wall surface is waterproofed with waterproof mortar 2, etc. do. Further, the tank body 4 is installed on the foundation 3 and fixed with a band 5. The space between the tank body 4 and the concrete wall 1 is filled with dry sand 6, and then the upper end opening of the concrete wall 1 is sealed with reinforced concrete concrete 7.

Also, to inspect whether there is any leakage of fuel from the inside of the tank body 4 into the tank storage room R sealed by the concrete wall 1 and the concrete M7, or whether there is any leakage of moisture from underground into the tank storage room R. The leak detection tube 8 is penetrated through the concrete cover 7 and inserted into several suitable positions in the dry sand 6, and a seal plug 9 is attached to the top of the detection tube 8 to periodically check for leakage. . A liquid fuel pipe 'M4 [10] for lubricating the tank body 4 and supplying fuel in the tank body 4 to others is piped from the tank body 4 through the concrete wall 1. 1.1 The tank body 4 is connected to a fuel injection pipe, an oil feed pipe, an oil return pipe, a vent pipe, etc., which are collectively referred to as liquid fuel pipes 10 in this specification. In addition, numeral 11 is the manhole cylinder, 12° 13 is the internal inspection of the tank body 4,
This is a cover plate for checking 1ffl.

However, the first liquid fuel storage device has the following (a) to (
D) There was a problem.

(a) Penetration part a of the liquid fuel pipe 'M410 through the concrete wall 1, penetration part b of the leakage detection tube 8 with the concrete cover 7,
If an abnormality occurs in the waterproof part such as the penetration part C between the manhole cylinder 11 and the concrete cover 7, or cracks occur in the concrete wall 1 or the concrete M7, the waterproofing of the tank storage room R becomes incomplete. Even if the tank body 4 is healthy, there is a problem in that water enters the tank storage chamber R and wets the dry sand 6, accelerating corrosion of the tank body 4.

It should be noted that the moisture that has entered the dry sand 6 cannot be removed later or re-dried, and there is a problem that once the dry sand 6 contains moisture, it almost loses its function as the dry sand 6. .

(b) Concrete walls 1 are often constructed outdoors;
During construction, if it rains while the dry sand 6 is being filled, the dry sand 6 will get wet with the rain, causing the same problem as in (a) above.

(c) In the process of constructing the concrete wall 1, a concrete cover 7 is placed after filling with dry sand 6, but the water in the fresh concrete permeates into the dry sand 6, reducing its function.

(d) In order to prevent the above-mentioned problems from occurring, the construction requires the utmost care, and the construction is performed by excellent workers, and sufficient knowledge and experience in the work is required, resulting in a rise in construction costs. , construction usually takes a considerable amount of time.

(Second liquid fuel storage device) Next, the second storage device will be explained with reference to FIG. Fix it. In this case, the tank body 4 is coated with a corrosion-resistant coating 15 on its outer surface to prevent corrosion. This corrosion protection work will be performed in accordance with the materials and construction methods stipulated by the Fire Service Act.

Foundation concrete) 14 has multiple supports 16 (4 at the four corners of the foundation concrete 14, or 6 to 8 at any location)
A concrete cover 17 made of reinforced concrete is placed on the upper end of this support column 16. Leakage detection tubes 8 for inspecting the presence or absence of leakage in the tank body 4 are provided at several suitable locations underground in the vicinity of the tank. The liquid fuel pipes 10 are piped underground, with or without penetrating the manhole cylinder 11.

However, this second fuel storage device had the following problems.

(a) If the tank body 4 corrodes and the fuel inside the tank body leaks, it will leak out and spread underground because there is no partition wall.
The soil becomes contaminated and a fire hazard arises. Therefore, the Fire Service Act prohibits installation using this construction method when there are underground structures such as tunnels, subways, underground malls, etc. in the vicinity, and various construction restrictions are set.

(b) Since soil is in contact with the tank body 4, careful work is required to avoid pinholes and the like when applying the anticorrosion coating 15 to the tank.

(C) Since soil is in contact with the tank body 4, if the groundwater level becomes high, buoyancy will be applied to the tank body 4, and there is a possibility that the tank body 4 will float up.

Therefore, it is necessary to take anti-corrosion measures to ensure sufficient strength of the band 5 and the bolts on the base 3 that fix it, and to prevent them from corroding.

(d) When a leak of a dangerous substance is detected by the leak detection tube 8, the dangerous substance has often already spread in the vicinity, which often results in a delay in response.

In addition to the above, there is a problem similar to that of 8(d) between the first fuel storage device.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an external tank with a predetermined space attached to an internal tank for storing liquid fuel, and a dry fuel tank in the space. The method is to fill it with non-combustible heat insulating material such as sand.

(Function) By adopting the above-mentioned means, the present invention functions as follows.

Since underground moisture is prevented from entering the space from the external tank and the internal tank is protected by the external tank, the durability of the internal tank is improved. Furthermore, even if the liquid fuel in the internal tank leaks, it will remain in the external tank and will not leak outside.

Furthermore, when the tank is actually buried underground, the buoyancy of the groundwater is reduced by the weight of the non-combustible heat insulating material, thereby preventing the tank from floating up.

(Example) Hereinafter, an example embodying the present invention will be described based on FIGS. 1 and 2.

As shown in Fig. 1, the internal tank 2 has a cylindrical shape with a sealing plate.
A cylindrical inner manhole tube body 22 is welded to the upper center of the manhole body 1 in a watertight manner, and a cover plate 23 is attached to the upper opening of the manhole body 22 with a bolt (not shown) through a gasket (not shown).
It is tightened and fixed.

At the upper part of the internal tank 21, an outer manhole cylinder 24 is welded to stand upright and fixed in a watertight manner so as to surround the inner manhole cylinder 22. The external tank 25 is installed at a predetermined interval, that is, with a space S, so as to cover the
The portion to be joined to the outer manhole cylinder body 24 is watertightly joined by welding. In addition, an input port 25a for filling the space S with dry sand 6 is formed at two places on both left and right sides of the upper part of this external tank 25. After filling the dry sand 6, a sealing lid 26 is attached by welding. It is joined and fixed in a watertight manner. In place of the dry sand 6, an effect equivalent to that,
In other words, any material may be used as long as it is nonflammable, has heat insulating properties, and has a considerable weight. Note that a plurality of spacers 27 are interposed between the internal tank 21 and the external tank 25.

The outer surfaces of the external tank 25 and the outer manhole cylinder 24 are coated with anti-corrosion coating 15 similar to the conventional one to prevent corrosion.
is applied.

A plurality of liquid fuel pipes IO are welded and fixed to the lid plate 23 in a watertight manner so that liquid fuel such as gasoline can be injected into the internal tank 21 and led out to the outside. Incidentally, the fuel pipes 10 are joined in the middle by a flange joint 28.

Inside the space S, a dedicated detection tube 29 for specifically detecting the leakage of hazardous substances in the internal tank 21 and the intrusion of underground water due to corrosion of the external tank 18 penetrates the external tank 25 and is installed inside the space S. What are the detection tube 29 and external tank 25? Watertightly joined and fixed with 8 contacts. The seal plug 9 at the inspection port of the dedicated detection tube 29 needs to be highly watertight to prevent rainwater etc. from entering the dry sand 6.

The double-structured liquid fuel storage tank constructed as described above is buried underground in almost the same manner as the construction method of the second liquid fuel storage device described in the conventional section, but with some differences. This will be explained based on FIGS. 3 and 4.

As shown in FIG. 3, the upper end of the dedicated detection tube 29 penetrates the concrete M17 and is exposed to the ground, and near the outside of the external tank 25 is a leak detection tube for detecting fuel leakage around the tank. A tube 8 is buried, and its upper end also passes through the concrete lid 17 like the dedicated detection tube 29.

Further, all of the liquid fuel pipes 10 are piped underground from the cover plate 23 through the outer manhole cylinder 24.

Now, in the embodiment of the present invention, the tank has a double structure consisting of an internal tank 21 and an external tank 25, and the space S is filled with dry sand 6, so that moisture in the ground is absorbed into the external tank 25.
This prevents the particles from entering the space S. Also, since the internal tank 21 is protected by the external tank 25,
The durability of the internal tank is improved. Furthermore, even if the liquid fuel in the internal tank 21 leaks, it remains in the external tank 25 and does not leak outside, thereby preventing the occurrence of fire and soil contamination.

In addition, since the space S between the internal tank 21 and the external tank 25 is filled with dry sand 6, its weight prevents it from floating up due to the buoyancy of water when the tank is actually buried underground. be able to.

Further, there is no need to consider the watertightness between the dedicated detection tube 29 and the concrete M17 and the watertightness between the concrete M17 and the cover plate 13, and the dedicated detection tube 29 can be welded by penetrating the external tank 25. , the watertightness of the penetrating portion d is also ensured.

In the above embodiment, the dedicated detection tube 29 was provided in the space S, and the leakage detection tube 8 was provided outside the tank. It is possible to easily determine whether the leakage is due to leakage. In other words, if water is detected by the dedicated detection tube 29, it is a leak from the external tank 25, and if oil is detected, it is a leak from the internal tank 21.
Furthermore, if oil is detected in the leak detection tube 8, it can be determined that the oil is leaking from the liquid fuel pipes 10.

Effect of the invention As detailed above, the present invention has the following effects.

■ Even if the fuel in the internal tank 21 leaks, the external tank 2
5, and prevents it from flowing out and spreading underground, preventing fires and soil contamination.

■ Filling with non-combustible insulation material can be done at the factory, making it possible to prevent rainwater from entering during construction.

■ The internal tank 21 is covered by the external tank 25,
Since the non-combustible insulation material is sealed by the external tank 25, it is possible to prevent underground water and rainwater from entering the non-combustible insulation material.
Non-combustible insulation can be kept dry at all times.

■ Since the space S is filled with a nonflammable heat insulating material, the weight of the entire tank increases, and it is possible to prevent the tank from floating due to the buoyancy of groundwater.

■ Even if corrosion occurs in the external tank 25 and underground water infiltrates the non-combustible insulation material, there will be a considerable amount of time before the internal tank 21 is affected, and the dedicated detection tube 29 will detect the abnormality. Even if you detect it and take countermeasures, you can respond adequately.

■ Even when applied to the construction method of the second liquid fuel storage device described in the conventional section, it is safe and the construction cost can be significantly reduced.
The construction period will also be significantly shorter than that of the conventional No. 1 liquid fuel storage device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the central part showing an embodiment of the liquid fuel storage tank of the present invention, FIG. 2 is a cross-sectional view taken along line 8-A in FIG.
Fig. 3 is a cross-sectional view showing a liquid fuel storage tank buried underground, Fig. 4 is a plan cross-sectional view showing the liquid fuel storage tank also buried underground, and Fig. 5 shows a conventional first liquid fuel storage device. The sectional view and FIG. 6 are sectional views showing the same conventional second liquid fuel storage device. Dry sand 6 as a non-combustible heat insulating material, liquid fuel pipes 1O1 internal tank 21, external tank 25, space S. Ln 1 0q 2 Σ ~ spit

Claims (1)

[Claims] 1. A liquid fuel underground storage tank characterized in that an external tank is attached to an internal tank for storing liquid fuel with a predetermined space, and the space is filled with a nonflammable heat insulating material such as dry sand.