JPH04203595A - Method of lowering roof of inner tank in double shell tank - Google Patents

Abstract

PURPOSE:To precisely and simply lower the roof of an inner tank by sealing between the outer peripheral part of the inner tank roof and the upper end part of the inner tank side plate, and by charging and discharging air pressure to and from the inside of the inner tank side plate. CONSTITUTION:A seal member 14 is circumferentially laid between the outer peripheral part 5a of a suspended inner roof 5 and the upper end part 7a of an inner tank side plate 7 so as to seal the inside of the inner tank side plate 7. When air pressure is charged in the inside of the inner tank side plate 7 from a blower 13, the inner roof 5 is floated up and supported since the inside of the inner tank side plate 7 is sealed with the seal member 14. In this condition, if bolts 12 in a coupling device for coupling inner and outer tank roofs 4, 5 are removed so as to release the coupling therebetween, when a valve 17 in a discharge pipe 16 is opened so as to discharge the air pressure from the inside of the inner tank side plate 7, the buoyancy of the inner tank roof 5 is gradually decreased, and accordingly, it is lowered onto the upper end part 7a of the inner tank side plate 7. Thereby it is possible to simply lower the inner tank roof 5 without the necessity of a large number of workers.

Description

[Detailed Description of the Invention] Industrial Application Field 1 The present invention is a double shell tank! f4 When installing the tank, the outer tank roof and inner tank roof are air-laid, and the outer tank roof is fixed to the outer tank side plate (2), and the inner tank roof is lowered onto the inner tank side plate (2). 4. Conventional technology regarding the method for lowering the inner tank roof of a heavy-shell tank] Generally, when building a double-shell tank on the ground to store low-temperature liquids such as LPG or LNG, the method is as shown in Figure 2. After constructing the foundation 1 on the ground, the outer tank side plate 2 is erected on the foundation 7, and the outer tank roof 4 and inner tank roof 5 are constructed using the bottom 3 of the outer tank side plate 2. The outer tank roof 4 and the inner tank roof 5 are joined together with a large number of rods 6, and after these roofs 4 and 5 are air-raised to fix the outer tank roof 4 on the outer tank side plate 2, the outer tank roof 4 is fixed on the outer tank side plate 2. When the inner tank side plate 7 is erected and the inner tank roof 5 is lowered onto the inner tank side plate 7, the rod 6 is loosened to lower the inner tank roof 5.

[Problem to be solved by the invention] By the way, in the above method, in order to lower the inner tank roof 5, it is necessary to loosen a large number of rods 6 at the same time. Since a load is applied to the rod 6, it is difficult to loosen the rod 6, and a large number of workers are required for this work.

The present invention was created to solve the above-mentioned problems, and its purpose is to provide a method for lowering the inner tank roof of a double-shell tank, which allows the inner tank roof to be lowered accurately and easily. be.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides a double shell tank with m
In order to construct the outer tank roof, the outer tank roof and the inner tank roof are joined together within the outer tank side panels that have been erected in advance, and the roof is air-raised to replace the outer tank roof with the above-mentioned outer tank side panels.
In this method, the outer circumference of the inner tank roof suspended from the outer tank roof and the upper end of the inner tank side plate are suspended from the outer tank roof. After supplying pressurized air into the inner tank side plate and floating and supporting the inner tank roof using the air pressure, the connection between the outer tank roof and the inner tank roof is released, and the inner tank roof is separated from the inner tank roof. The inner tank roof is lowered onto the inner tank side plate while releasing the pressure inside the tank side plate. [Function] According to the above structure, when lowering the inner tank roof, the inner tank side plate is lowered. After releasing the connection between the outer tank roof and the inner tank roof while floating and supporting the inner tank roof by supplying pressurized air inside, the inner tank roof gradually loses its buoyancy and floats above the inner tank side plate. descend to

Furthermore, at this time, by adjusting the release of pressurized air, the inner tank roof can be lowered quietly, without damaging the inner tank roof.

Additionally, this allows for a dramatic reduction in the number of workers.

[Example code] An embodiment of the present invention will be described based on the drawings.

FIG. 1 shows an example of a double shell tank in which the method of the invention is practiced.

In Fig. 1, 8 is a double-shelled tank, and when constructing this double-shelled tank 8, after constructing a foundation on the ground, the outer tank side plate 2 is erected on the foundation 1, and the outside of the tank is An outer tank roof 4 and an inner tank roof 5 are constructed at the bottom part 3 within the tank side plate 2, and these outer tank roof 4 and inner tank roof 5 are integrally joined.

At this time, the outer tank roof 4 and the inner tank roof 5 are connected by a connecting device 9. This connecting device 9 is provided in multiple stages at intervals along the circumferential direction on the outer periphery of the inner tank roof 5, and each connecting device 9 has an outer FjlO that stands upright on the inner tank roof 5, and one end that connects to the outer tank roof. 4, and an inner cylinder 11 whose other end is slidably inserted into the outer cylinder 10.
o and the inner cylinder 11 are connected with bolts 12.

Next, the outer tank roof 4, inner tank roof 5, and blower 13 are combined.
After fixing the outer tank roof 4 on the outer tank side plate 2 by air raging with air pressure, the inner tank side plate 7 is erected on the foundation 1, and the inner tank roof 5 is lowered onto the inner tank side plate 7. Then, the inner tank roof 5 is attached on the inner tank side plate 7, and the double shell tank 8 is constructed.

By the way, in the above description, when lowering the inner tank roof 5 suspended from the outer tank roof 4, as shown in FIG. A plurality of guide members 1 that seal the upper end 7a by stretching a sealing material 14 between them and guide the outer periphery 5a of the inner tank roof 5 along the inner peripheral surface of the upper end 7a of the inner tank side plate 7.
In addition, a discharge pipe 16 for discharging pressurized air is connected to the top of the inner tank roof 5 via a valve 17, and the blower 13 and the inner tank side plate 7 are connected by a conduit 13a.

Next, when lowering the inner tank roof, if pressurized air is supplied from the blower 13 into the inner tank side plate 7, the inside of the inner tank side plate 7 is sealed with the sealing material 14, so the inner tank roof 5 is lowered. , the air becomes suspended and supported by the air pressure. In this state, the ports 1-12 of the connecting device 9 connecting the outer tank roof 4 and the inner tank roof 5 are removed to release the connection between the outer tank roof 4 and the inner tank roof 5, and the above-mentioned When the valve 17 of the discharge 'IF 16 is opened to release the pressure inside the inner tank side plate 7, the inner tank roof 5 gradually loses its buoyancy and falls onto the upper end 7a of the inner tank side plate 7.

When releasing pressurized air, by adjusting the opening degree of the valve 7 of the release valve 116 to adjust the release of the pressurized air, the lowering speed of the inner tank roof 5 can be adjusted, and the inner tank roof 5 can be moved quietly. Since it can be lowered onto the inner Wi side plate 7, the inner tank roof 5 will not be damaged.

Also, during this descent, the inner tank roof 5 is
Since the inner cylinder 11 slides inside the outer cylinder 10, its balance is maintained, and the outer peripheral part 5a of the inner tank roof 5 is guided by the guide member 15 on the upper part 7a of the inner tank side plate 7. It can be lowered onto the inner tank side plate 5 with high precision.

In this way, since the inner tank roof 5 is lowered while being floated and supported by pressurized air, the lowering work of the inner tank roof 5 can be easily performed without requiring a large number of workers as in the past. .

Effects of the Invention: 1 According to the present invention, the inner tank roof is lowered while being floated and supported using pressurized air, so the lowering work can be carried out with high accuracy, in a short time, and extremely easily, and the number of workers can be reduced compared to the conventional method. It exhibits excellent effects such as being able to dramatically reduce

[Brief explanation of the drawing]

FIG. 1 is a schematic overall cross-sectional view showing a double shell tank for carrying out the method of the present invention, and FIG. 2 is a schematic overall cross-sectional view showing a conventional example. In the figure, 2 is the outer tank side plate, 4 is the outer tank roof, 5 is the inner tank roof, 5
7 is an inner tank side plate, 7a is an upper end thereof, 8 is a double shell tank, 13 is a blower, 114 is a sealing material, 16 is a discharge pipe, and 17 is a valve. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd. Ishikawajima Tank Construction Co., Ltd.

Claims (1)

[Claims] 1. In order to construct a double shell tank, the outer tank roof and the inner tank roof are joined together within the outer tank side panels that have been erected in advance, and the outer tank roof is attached to the outer tank by air raising the roof. After fixing it on the tank side plate, set the inner tank side plate upright,
In the method of lowering the inner tank roof onto the inner tank side plate, a seal is formed between the outer periphery of the inner tank roof suspended from the outer tank roof and the upper end of the inner tank side plate, and the inner tank roof is lowered onto the inner tank side plate. After supplying pressurized air to float and support the inner tank roof using the air pressure,
The double tank roof is characterized in that the connection between the outer tank roof and the inner tank roof is released, and the inner tank roof is lowered onto the inner tank side plate while releasing the pressure inside the inner tank side plate. How to lower the inner tank roof of a shell tank.