JPS61216978A - Construction of double shell tank - 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] [Field of Industrial Application] This invention relates to an improvement in the construction method of a double-shelled tank, and in particular, to a method that enables construction in a short time while carrying out pressure tests on the inner and outer tanks. .

[Conventional technology]

2. Description of the Related Art Double-shelled tanks are generally used to store low-temperature liquids such as liquefied propane (LPG) and liquefied natural gas (LNG) to prevent risks such as leakage.

For example, as shown in Figure 4, for a low-temperature storage tank made of concrete with an outer tank, which is one type of double shell tank, a foundation 1 made of insulating concrete is laid on the ground surface, and the outer tank 2 is integrated with this foundation 1.
Build a concrete or reed wall 3 that will become the side wall of the tank, cover the inner surface of these concrete walls 3 and the foundation 1 with a seal plate 4 such as a steel plate, and insert a heat insulating material 5 on the seal plate 4 to form an inner tank 6. A construction method is used in which the roof 7 of the outer tank 2 is constructed to cover the inner tank 6.

In such a low-temperature storage tank, in order to prevent danger in the event that the low-temperature liquid in the inner tank 6 leaks, the concrete wall 3 serving as the side wall of the outer tank 2 is made to function as a liquid barrier.

For this reason, the concrete wall 3 needs to be strong enough to withstand the pressure of the leaked low-temperature liquid, and it is preferable to perform a pressure test to confirm this after construction.

[Problem that the invention seeks to solve]

However, conventionally, the airtightness of the inner tank 6 has been confirmed by a vacuum test, and the pressure resistance strength has been confirmed by a water filling test, but no tests have been conducted for the outer N2 tank.

Therefore, when trying to perform a water filling test by filling water between the outer tank 2 and the inner tank 6, the following problems arise.

(2) The heat insulating material 5 interposed between the foundation 1 and the inner tank 6 is usually made of a highly water-absorbing material such as a perlite block or foam glass, and therefore loses its function.

Additionally, if water pressure equivalent to leaked low-temperature liquid is applied between the outer tank 2 and the inner tank 6, the same pressure will be applied to the inner tank 6 from the outside, causing the inner tank 6, which is not designed for external pressure, to deform. or buckle.

■ Therefore, after constructing the concrete wall 3 and seal plate 4 of the foundation 1 and outer tank 2, it is possible to conduct a water filling test before constructing the inner tank 6, but the inner tank cannot be constructed until the test is completed, so now If the inner and outer tanks are constructed at the same time, the comparison period will be very long.

In addition, while a large amount of water is required for the water filling test of the outer tank,
Unless this water is drained, the inner tank cannot be constructed, and when testing the inner tank, a large amount of water is required again.

This invention was made in view of the above-mentioned conventional technology, and it is possible to reduce the amount of water required for testing, without prolonging the construction period.
The purpose of this invention is to provide a method for constructing a double shell tank that can be constructed while conducting water filling tests for the inner and outer tanks.

[Means for Solving Problem I211] The method for constructing a double shell tank of the present invention that achieves the above object is to construct an inner tank on a foundation with a heat insulating material in between, and to construct an outer tank to cover this inner tank. After constructing the tank, the bottom of the inner tank and the side walls of the outer tank are made watertight with a temporary seal plate, and a water filling test is performed on the inner tank. Next, some of the water in the inner tank is injected between the inner and outer tanks to seal the outer tank. The present invention is characterized in that after a water filling test is conducted and the water is drained, the temporary seal plate is cut to separate the inner and outer tanks.

(Function) After laying the foundation, constructing the inner and outer tanks at the same time, and building both the inner and outer tanks to the point where water filling tests can be performed.
The bottom of the inner tank and the side wall of the outer tank are connected in a watertight manner using a temporary seal plate to prevent water from reaching the insulation material on the foundation. First, water is poured into the inner tank and a water filling test is performed. Then, this water is After conducting a water filling test on the outer tank with a portion placed between the inner and outer tanks with water filled in both the outer and outer tanks, the water is drained, the temporary seal plate is cut, and the inner and outer tanks are uncoupled to become independent. It is.

By doing this, it is possible to construct the inner and outer tanks in parallel, thereby preventing an extension of the construction period, making it possible to test the inner and outer tanks with the amount of water necessary for the water filling test of the inner tank, reducing the amount of water required, and reducing the amount of water used when testing the outer tank. The inner tank is also filled with water to prevent deformation or damage to the inner tank.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1 showing the process, the method for constructing a double shell tank of the present invention is as follows: First, a foundation 10 is laid on the ground surface, and a seal plate 11 is installed on the foundation 10 to prevent leakage of low-temperature liquid. After the installation, a heat insulating material 12 such as a perlite block or foam glass is installed. At the same time, a concrete wall 14 constituting the outer tank 13 is constructed, and a seal plate 15 is provided on the inner peripheral surface to prevent the leakage of low-temperature liquid, and is connected to the bottom seal plate 11 by seam welding etc. to make it airtight and watertight. do.

Thereafter, the inner tank 16 is constructed on the heat insulating material 12, and the parts of the outer tank 13 other than the concrete wall 14 are constructed.

Then, the outer tank 13 is removed without water intruding into the heat insulating material 12.
A temporary seal plate 17 having a cross-section shown enlarged in FIG. 16 and the edge with the seal plate 15 are seam welded.

Inner tank 16 and outer tank 1 in which this temporary seal plate 17 is provided
In the space between 3 and 3, an anchor strap 18 for supporting the inner tank 16 is welded to the outer wall of the inner tank 16 and fixed at the underground part that penetrates the foundation 10, so this part of the anchor strap 18 is also Make it watertight by seam welding, etc.

After the construction of the inner and outer tanks 16 and 13 is completed, a water filling test is performed.First, as shown in FIG. 1(b), a predetermined amount of water is poured into the inner tank 16 to check its pressure resistance.

Next, a water filling test is conducted to confirm the pressure resistance of the concrete wall 14 of the outer tank 13, but in this case, the first
As shown in Figure (C), the water in the inner tank 16 is pumped up with a pump or the like and placed between the inner tank 16 and the outer tank 13.

In this case, the bottom between the inner tank 16 and the outer tank 13 is completely watertight with a temporary seal plate 17, so the insulation material 1
Since this space volume is smaller than that of the inner tank 16, a considerable amount of water also enters the inner tank 16, and there is almost no pressure difference between the inside and outside of the inner tank 16. This can prevent the inner tank 16 from being deformed or damaged.

When the water filling test of the inner tank 16 and the outer tank 13 is completed in this way, the water in the inner tank 16 and the outer tank 13 is drained, and the temporary seal plate 17 is cut, for example, at the part shown by the dashed line in FIG. 16 and the outer tank 13 are in an independent state. And if necessary, temporary seal plate 17
Try to remove it.

After this, a pearlite diaphragm 19 is installed between the inner tank 16 and the outer tank 13, and granular pearlite 20 is filled to form a heat-insulating layer, completing a double shell tank as shown in Figure 3. do.

In addition, although the above-mentioned example explained the case of an above-ground tank, it can be similarly applied to an underground tank.

〔Effect of the invention〕

As specifically explained above in conjunction with the embodiments, according to the present invention, after the foundation is laid, the inner tank is constructed via a heat insulating material, and at the same time, the outer tank is also constructed, and the bottom of the space between them is filled with a temporary seal plate. Since it is made watertight, it is possible to perform a water filling test on the outer tank after constructing the inner tank, and the construction period can be significantly shortened compared to the case where the water filling test is performed after constructing the outer tank and then the inner tank is constructed.

In addition, since the water filling test of the outer tank can be performed using part of the water in the inner tank, the amount of water used can be reduced significantly compared to when testing the inner and outer tanks separately, and the water used during the test of the outer tank can be significantly reduced. Since the inner tank is filled with water, external pressure will not be applied to the inner tank, which has an internal pressure resistant structure, to cause deformation such as buckling or damage.

Furthermore, after the water filling test of the inner and outer tanks, the temporary seal plate is cut, so even if the inner tank is thermally shrunk due to storage of low-temperature liquid in the inner tank, this effect will not affect the outer tank, etc.

[Brief explanation of drawings]

Figures 1 to 3 show an example of the method for constructing a double-shelled tank of the present invention, with Figure 1 being a process diagram, Figure 2 being an enlarged perspective view of the temporary seal plate, and Figure 3 being completed. FIG. 4 is a cross-sectional view of a conventional double-shell tank. 10...Foundation, 11...Seal plate, 12...
- Insulation material, 13... Outer tank, 14... Concrete wall, 15... Seal plate, 16... Inner tank, 17.
... Temporary seal plate, 18... Anchor strap, 19... Pearlite diaphragm, 20... Granular pearlite.

Claims (1)

[Claims] After constructing an inner tank on the foundation with insulation material and constructing an outer tank to cover this inner tank, the bottom of the inner tank and the side walls of the outer tank were made watertight with a temporary seal plate, and the inner tank was tested with water. Then, a part of the water in the inner tank is injected between the outer and outer tanks to perform a water filling test on the outer tank, and after draining, the temporary seal plate is cut to separate the inner and outer tanks. How to build a double shell tank.