JPH08193909A - Coaxial vertical cylindrical tank and leak test method therefor - Google Patents

Abstract

PURPOSE: To obtain an economical coaxial vertical cylindrical tank and a method of a leak test by filling water therefor inn which the quantity of pure water required for testing the tank is decreased while shortening the time required for obtaining the pure water and the labor cost is reduced. CONSTITUTION: The inventive tank comprises a vertical cylindrical tank 2 of intermediate diameter, and a flexible cylindrical tank body 4a of small diameter comprising a flexible membrane supported coaxially on the inside of the tank 2. When the tank is tested for leakage by filling water, the flexible tank body 4a is filled with sea water and the gap between the flexible tank 4a and the tank 2 is filled with pure water. Alternatively, the flexible tank body 4a is filled with sea water and the gap between the flexible tank body 4a and the tank 2 is filled with a liquid having specific gravity substantially equal to that of the sea water and causing no corrosion of the tank 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial vertical cylindrical tank and a water filling test method therefor.

[0002]

2. Description of the Related Art Conventionally, in LNG tanks, crude oil tanks, etc., when a tank is completed, fresh water is poured into the tank up to a predetermined liquid level to perform a pressure resistance test of the tank.

[0003]

However, such a water filling test method has the following problems in a region where it is difficult to obtain a large amount of fresh water, such as the Middle East. (1) It is difficult to secure the required amount of fresh water. (2) Since it takes a long time to obtain and secure fresh water, the construction period will be prolonged. (3) The price of fresh water is high, which causes a high construction cost. Therefore, when constructing a tank in an area where it is difficult to obtain fresh water, such as the Middle East, the water for water filling test required when the tank is completed was manufactured by a desalination device and transported by fresh water stored in a temporary pond or by a tanker. Fresh water or seawater will be used. However, or will result in the use of very expensive water, which is undesirable because it rusts the tank. In particular, in the case of an LNG tank constructed of 9% Ni steel, the method cannot be adopted because seawater causes galvanic corrosion due to the fact that the weld is a dissimilar material.

The present invention has been proposed in view of such circumstances, and it is an economical coaxial system that reduces the amount of fresh water required for tank testing, shortens the time required to obtain the fresh water, and reduces the construction cost. An object of the present invention is to provide a vertical cylindrical tank and a water filling test method therefor.

[0005]

To this end, the tank structure according to claim 1 comprises a medium diameter vertical cylindrical tank and a flexible membrane coaxially supported inside the medium diameter vertical cylindrical tank. It is characterized by comprising a small-diameter vertical cylindrical flexible tank body.

According to the test method of claim 2, seawater is put into the small-diameter vertical cylindrical flexible tank body when the water filling test of the tank of the first embodiment is performed, and the small-diameter vertical flexible tank body and the medium-diameter The feature is that fresh water is put in between the vertical cylindrical tank.

According to the test method of claim 3, when performing the water filling test of the tank of claim 1, seawater is put into the small-diameter vertical cylindrical flexible tank body, and the same small-diameter flexible tank body and its medium diameter are used. It is characterized in that it has a specific gravity that is almost the same as that of seawater between it and a vertical cylindrical tank, and that it contains a liquid that does not corrode the medium diameter vertical cylindrical tank.

[0008]

According to such a configuration, the following operation is performed. (1) Since the internal and external pressures of the flexible film are balanced,
No film stress is generated in the circumferential direction. By the way, put seawater (specific gravity 1.03) inside the tank and water (specific gravity 1.00) outside.
If the membrane diameter is 70m and the water depth is 34m,
The film stress due to the difference in specific gravity is σ = PR = (1.03-1.00) × 3.4 × 3500
= 357 kg / cm 2, and the film strength is 30 to 120 kg / cm or more. However, in practice, it is necessary to take a safety factor, so the generated stress must be 30 kg / cm or less. Therefore, it is necessary to balance the internal and external pressures. (2) In addition, when water having a difference in density between the inside and the outside of the flexible tank is put to the same water level, a pressure difference occurs due to the difference. Now, inside the flexible tank, seawater (density 1.03),
When water (density 1.00) is put into the outside, assuming that the diameter of the flexible tank body is 70 m and the water depth is 34 m, the pressure difference Δp at the deepest part due to the density difference is Δp = (1.03-1.00 ) × 10 ⁻³ × 3400 =
0.102 kgf / cm It is necessary to employ a flexible tank body that withstands this differential pressure.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.
1 is a longitudinal sectional view of a tank showing the first embodiment thereof, FIG. 2 is a longitudinal sectional view of a tank showing the second embodiment thereof, and FIG. 3 is a partial sectional side view showing the flexible inner tank of FIG. is there.

First, in the first embodiment shown in FIG.
Is an outer tub, and the outer tub 1 has a large-diameter vertical cylindrical shape that coaxially surrounds the inner tub 2 at appropriate intervals, and protects the outer surface of the medium-diameter vertical cylindrical inner tub 2 described later. . 2 is a medium-diameter vertical cylindrical inner tank which is coaxially and suspended vertically and horizontally supported inside the large-diameter vertical cylindrical outer tank 1, 3 is a suspended roof, 4 is a flexible membrane, and 5 is A small-diameter vertical cylindrical flexible tank body 4a, which is a membrane support material and is reinforced by the flexible membrane 4 and the membrane support material 5, is formed. 6 is seawater, and 7 is mixed water in which iron oxide powder or the like is mixed to have the same specific gravity as seawater.

According to such a structure, since most of the water required for the water filling test can use seawater, it is economical, and the portion that comes into contact with the tank is mixed water, that is, water. No worries.

Next, in the second embodiment shown in FIGS. 2 to 3, the same reference numerals as those in FIG. 1 denote the same members as those in the same drawing, and the present second embodiment is greatly different from the first embodiment. Is in the structure of a flexible tank made of the flexible membrane and its water filling test procedure.

In the above figure, 4a is a flexible tank body made of a flexible film which is reinforced with a cloth 9 and is watertight with rubber 10 or the like.
Reference numeral 8a is a hoop-shaped reinforcing material for reinforcing the flexible film, and is a member for ensuring the deformation and strength of the flexible film caused by the difference in density.

Inside the inner tank 2, a flexible tank body 4a made of rubber or the like having a diameter slightly smaller than the inner diameter of the inner tank 2 is installed.
Water such as seawater is put in a, and fresh water 7a that does not harm the tank such as fresh water is put between the inner tank 2 and the flexible tank body 4a. The pressure difference due to the density difference of water inside and outside the flexible tank body at this time can be endured by reinforcing the outer surface of the flexible tank body 4a made of rubber or the like.

[0015]

According to the structure of the second embodiment as described above,
Since most of the water required for the water filling test can use seawater etc., it is economical, and since water can be used in the part that touches the tank, there is no risk of corrosion of the tank material.

In short, according to the first aspect of the present invention, a small-diameter vertical cylindrical flexible tank including a medium-diameter vertical cylindrical tank and a flexible film coaxially supported inside the medium-diameter vertical cylindrical tank. An economical coaxial vertical cylindrical tank that reduces the amount of fresh water required for the tank test, shortens the time required to obtain the tank, and reduces the construction cost, and its water filling test method. Therefore, the present invention is extremely useful industrially.

According to the invention of claim 2, when performing the water filling test of the tank of claim 1, seawater is put into the small diameter vertical cylindrical flexible tank body, and the small diameter flexible tank body and the inside Economical coaxial vertical cylinder that reduces the amount of fresh water required for tank testing, shortens the time required to obtain it, and reduces construction costs by inserting fresh water between the tank and the vertical cylindrical tank. INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially because a tank-shaped tank and a water-filling test method thereof are obtained.

According to the invention of claim 3, when performing the water filling test of the tank of claim 1, seawater is put into the small-diameter vertical cylindrical flexible tank body, and the small-diameter flexible tank body and the inside The amount of fresh water required for the tank test is reduced by adding a liquid that has almost the same specific gravity as seawater with the diameter cylindrical tank and does not corrode the medium diameter cylindrical tank. INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially because an economical coaxial vertical cylindrical tank and a water filling test method therefor can be obtained which shortens the time required for acquisition and reduces the construction cost.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

FIG. 3 is a partial vertical cross-sectional side view showing the flexible inner tank of FIG.

[Explanation of symbols]

 1 Outer Tank 2 Inner Tank 3 Suspended Roof 4 Flexible Membrane 4a Flexible Tank Body 5 Flexible Membrane Support 6 Seawater 7 Iron Oxide Powder Mixed Water 7a Fresh Water 8 Hoop Reinforcing Material 8a Hoop Reinforcing Material 9 Cloth 10 Rubber

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshikazu Kano 12 Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Ryohichi Engineering Co., Ltd. Honmoku Plant

Claims (3)

[Claims] 1. A medium diameter vertical cylindrical tank, and a small diameter vertical cylindrical flexible tank body made of a flexible film coaxially supported inside the medium diameter vertical cylindrical tank. Characteristic tank. 2. When performing the water filling test of the tank according to claim 1, seawater is put into the small-diameter vertical cylindrical flexible tank body,
A water filling test method for a tank, wherein fresh water is introduced between the small-diameter flexible tank body and the medium-diameter vertical cylindrical tank. 3. When conducting the water filling test of the tank according to claim 1, seawater is put into the small diameter vertical cylindrical flexible tank body,
The water filling of a tank characterized by having a specific gravity between seawater of the same diameter and the medium diameter vertical cylindrical tank that is almost the same as seawater, and containing a liquid that does not corrode the medium diameter vertical cylindrical tank. Test method.