JPS59211836A - Method for inspecting air-tightness of tank chamber - Google Patents

Abstract

PURPOSE:To make it possible to accurately judge the air-tightness inspection of a tank chamber by excluding an error due to temp. change, by comparering two tank chambers buried underground under the mutually same condition while reading the pressure difference between both tank chambers. CONSTITUTION:At first, on the confirmation of the shut-off with the atmosphere of the opening parts of tanks T1, T2, valves V1, V2 are closed and, subsequently, valves V3, V4 are opened. By this operation, the gas in a bomb B is injected into tank chambers R1, R2 through hoses H1, H2. After the completion of gas injection is confirmed by the flow of a galvanoscope F, the valve V4 is closed while the valves V1, V2 are opened and, subsequently, the valve V3 is closed. In this state, the liquid level of the colored liquid in a U-shaped tube is monitored for a difinite time. If tank chamber R2 is pierced with a hole, pressure is fallen by gas leakage and, therefore, the height of the liquid level in the U- shaped tube changes from a, b, to a', b' and it can be accurately judged that the air-tightness of the tank chamber R2 is not maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present application is an effective inspection method for inspecting underground tanks that are difficult to inspect for airtightness.

Karin Stand is one of approximately 60,000 locations across the country.
Each company has 3 to 4 underground tanks, and the total number of tanks is about 200,000.

Also, since all of them are made of iron plates2, it is thought that sooner or later the airtightness will be compromised due to corrosion.

If a hole opens in a tank, oil will leak into the ground, causing pollution and, since gasoline is highly flammable, there is also a risk of fire.

However, with the conventional inspection method of simply applying pressure to the tank and observing the pressure change, even if a pressure change occurs, it is difficult to determine whether it is due to a temperature change inside the tank or a minute hole. Therefore, it has been desired to develop an accurate airtightness inspection method.

The present invention has been proposed in view of the above-mentioned needs, and makes it possible to eliminate errors caused by temperature changes and make accurate determinations by comparing underground tanks with the same conditions.

The illustrated embodiment will be described below.

T1. T2 is the main body of the tank, which has tank chambers R1 and R2 formed inside, and is buried in the ground (q), with manholes Ml and N2 raised above it for injection, suction, and remaining amount measurement, respectively. opening Nl.

Nl, Nl, N2. N'2 and N2 are provided.

81.82 is a thermometer connected to openings Nl and N2 to measure the temperature inside tank chambers R1 and R2, Pi and P2 are plugs that close openings N'l and N'2, and Hl and N2 are plugs that close openings N'l and N'2. These ports are connected at one end to each opening Nl s N 2 and at the other end to a conduit communicating with the U-shaped tube ([J). The pipe (goods) has a colored liquid injected inside.9
It is made of crow-like transparent paulownia wood so that the colored liquid can be seen from the outside.

vl, v2. v3. v4 is a valve that opens or closes the pipe, respectively, (B) is a cylinder filled with compressed gas such as nitrogen, and (E) is a pressure reducing valve (q is the pressure reducing valve (g)). (F) is a galvanometer to check the presence or absence of waste flow, and l-13 is a connection hose.

In the above configuration, first, the openings N1 and N1 of the tanks TI and T2. Nl, N2. N2', N2. After confirming the connection with the atmosphere, pulp Vl*Vz'e is closed, and then pulp 7-V3. V4 f opens, thereby cylinder Φ
), the pressure reducing valve (g)), galvanometer αsu', hose
3. No. 4 Further, it passes through all of the hoses H1 and H2 and is injected into the tank chambers R1 and R2.

The end of the injection can be determined when the galvanometer (1') no longer shows a flow of scum. In addition, the reason why V22 and V22 were closed prior to injecting the scum was to prevent the colored liquid in the tube (B) from loosening from the tube (J) due to the force of the injected scum. After completing the injection of the liquid, close the valve 4 and check the thermometer Sl.

After confirming that the indicated temperature of S2 is at a level that does not affect the measurement, first open the valves vl and v2, and then close the pulp valve V3i.

By closing pulp ■3, tank chambers R1 and R2 will communicate only through the pipe (6)
) Since colored liquid is injected into the same, there is no real communication between them.

In this state, monitor the level of the colored liquid for one hour and
If both R1 and R2 are kept airtight, the liquid level will be the same height as a and b!'! l: However, if there is a hole in tank chamber R2, the scum will leak out and the pressure will drop, so the pressure in tank chamber R2 will be lower than that in tank chamber R1, so the liquid level will be a', b', and it can be accurately determined that the airtightness of the tank chamber R2 is not maintained. on the other hand,
In the case where the tank chamber R1 has a hole and is not kept airtight, the above explanation deals with comparing two tank chambers Pi, but it is also possible to compare three or more tank chambers. In this case, as shown by the two-dot chain line, valve ■5
．． Add v6'' IC and connect it to other tank chambers via valve ■6, first inject gas into all tank chambers so that they all have the same pressure and temperature, then close pulp ■4 and close valve ■1. .■Open 2, then close pulp v6 and close valve v3. At this time, valve v5 is open, so
First, compare the pressures in tank chamber R1 and tank chamber R2, then close valve 5 and open pulp chamber Vse.
It is possible to compare the pressure in the tank chamber R1 and the tank chamber connected via the valve 6.

In this example, one tank is formed with one tank chamber, but a tank with two or more tank chambers, such as a middle partition, is explained. It goes without saying that the determination can be made in the same manner as well.

On the other hand, the injected scum is not limited to nitrogen scum, but may be other inert gas or something like air, and the present inspection method uses a method of pressurizing the tank chamber.
A method of reducing the pressure can also be used. In this case, if the tank chamber R2 is not kept airtight, the liquid level will be as shown in a and b. On the other hand, if the tank chamber R1 is not kept airtight, the liquid level will be a and b. As detailed above, when using the inspection method according to the present invention, there is no need to compare the internal pressures of tank chambers that are buried underground, and the same environmental conditions can be obtained. The difference in the temperature of the tank chamber is virtually eliminated; that is, there is no pressure change due to temperature changes, and accurate judgments can be made.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the measurement of the pressure difference between two tanks. R1, R2... Tank chamber 81, 82... Thermometer (
B)...Cylinder (CI)...Tube a, a, a
, b, b, b-Liquid level patent applicant Tominaga Seisakusho Co., Ltd.

Claims (1)

[Claims] A step of isolating all openings of at least two tank rooms from the atmosphere inside the tank rooms of a business establishment where a plurality of mutually independent tank rooms are installed underground, and communicating both tank rooms. A tank buried underground, which consists of a step of making the inside of the tank chamber different from atmospheric pressure and then setting it to the same pressure, and then a step of cutting off communication between the tank chambers and reading the pressure difference between the tank chambers. How to check the airtightness of a room.