JPH0126946B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for converting an existing single deck type floating roof into a double deck type.

There are various types of floating roofs, but the main ones are single deck type and double deck type.

The former has a structure with a ring-shaped floating box (pontoon) on the outer periphery of the floating roof and a single-layer roof in the center. In the latter, the entire surface of the floating roof is made up of two layers of roof plates, and in the space between the two layers of roof plates, a rim plate that divides the roof concentrically and a partition plate (bulkhead) that divides the roof in the radial direction are inserted. The structure is watertightly separated from the pontoon, and is reinforced with struts, diagonals (truss), etc., as appropriate.

The double-deck type floating roof is effective in insulating heat from the outside air and stored liquid, and is therefore highly effective in preventing heat dissipation, so it is particularly useful when storing highly volatile liquids or when storing heated liquids. This is a suitable model.

In recent years, in floating roof storage tanks constructed with single decks, there are cases where the storage liquid is changed to a more volatile liquid than before, cases where the storage tank's heat retention performance is improved, and cases where heat absorption from the upper part of the roof plate is used. When improving to suppress evaporation loss of storage liquid,
Floating roofs are being converted into double deck types in various places.

As shown in Figure 1, the method of converting a conventional single-deck type floating roof into a double-deck type is to draw out all the stored liquid, lower the floating roof 1, support it on the bottom plate 3 via the deck posts 2, and then further A large number of frames 5 are arranged between the lower deck plate 4 and the bottom plate 3, and the rim plate 11, bulk head 6, truss 7, other accessories such as deck posts and nozzles, and the upper deck plate 8 are attached on the frames. The method used was to assemble a floating roof.

However, this method requires a large number of frames 5, and the equipment costs, transportation costs, assembly and disassembly costs are enormous, and account for a large portion of the floating roof modification cost. Another disadvantage was that dismantling the frame required work in a narrow space and was somewhat dangerous.

Furthermore, in the conventional method, when the floating roof is lowered onto the bottom plate, it is locally supported at the position of the deck post, so the entire floating roof is not level and is fixed with some degree of distortion or unevenness. was unavoidable. If many structural members were assembled in that state and the floating roof was floated above the storage liquid again after modification, excessive force would be applied to the deck and pontoons, posing a safety problem.

The present invention relates to a method for converting a single deck type floating roof into a double deck type without deformation or distortion without using multiple frames. After drilling holes in the deck plate surface of an existing single-deck type floating roof to remove roof drains, attaching the parts to be installed in advance, and closing the openings that are no longer needed, the entire floating roof is lowered. The floating roof is floated by injecting the minimum amount of water necessary for it to float completely into the storage tank, and after confirming leakage of the floating roof, the upper deck is assembled in that state.

The method of the present invention will be explained below with reference to the drawings (FIGS. 2 and 3).

FIG. 2 shows a state in which all the stored liquid has been extracted and the floating roof 1 has been lowered onto the bottom plate 3.

In this state, a new deck post sleeve 9 is attached.

In addition, the existing deck post sleeves that obstruct the assembly of the double deck truss 7, rim plate 11, and bulk head 6 should be removed and the blind plate 10
Install. In addition, a temporary support 16 made of a log or a steel pipe is inserted in place of the deck post at the location where the deck post sleeve 9 is to be replaced to temporarily support the floating roof. Furthermore, the installation of all accessories, such as a center sump, auxiliary sump, roof drain, etc., that penetrate through the existing deck plate 4 are completed.

Thereafter, as shown in FIG. 3, the entire floating roof 1 is completely separated from the bottom plate 3, and the minimum amount of water necessary for floating is injected into the tank to float the floating roof. At the same time as it ascends to the surface, confirm that there is no leakage from the lower deck that comes into contact with the liquid surface. Assemble the upper deck structure while floating and holding the existing deck plate horizontally. That is, from the inner rim plate 15 of the existing pontoon, the rim plate 11, bulkhead 6, truss 7, and rafter are assembled in this order toward the center of the floating roof, welding is repeated until the center is assembled, and finally the upper deck plate 8 is assembled.
are arranged and welded to the rafters to form a two-layered deck plate.

As is clear from the above explanation, according to the floating roof remodeling method of the present invention, there is no need for any frame for assembling the floating roof, and the number of man-hours and time required for assembling and disassembling the frame is also eliminated, thereby improving safety when remodeling the floating roof. In addition to significantly improving the performance, it is possible to shorten the construction period and significantly reduce construction costs.

Since the upper deck structure is assembled with the floating roof floating above the water surface and the existing deck plate held horizontally, it is possible to modify it to fit the shape of the floating roof when the tank is used, and the pontoon and deck plate It is possible to form a high-quality floating roof with good rainwater drainage performance and no deformation or distortion without applying excessive force to the roof.

It is possible to perform floating roof leakage inspection before floating the floating roof above the water surface and assembling the upper deck plate to cover it, making the inspection work extremely easy and ensuring the safety of the floating roof buoyancy. , we can provide a double deck type floating roof that is highly economical and safe.

It has excellent effects such as.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional floating roof remodeling method, and FIG. 2 is a sectional view showing an example of the state before assembly of the upper part of a deck according to the floating roof remodeling method of the present invention. FIG. 3 is a sectional view showing the state when the floating roof is floated from the state shown in FIG. 2 and the deck portion is assembled. 1... Floating roof, 2... Deck post, 3... Bottom plate, 4... Lower deck plate, 5... Frame, 6
... Bulk head, 7 ... Truss, 8 ... Upper deck plate, 9 ... Sleeve for newly installed deck post, 10 ... Blind plate, 11 ... Rim plate, 12 ... Tank side wall, 13 ... Pontoon, 14 ... Harishui,
15... Inner rim board, 16... Temporary support.

Claims (1)

[Claims] 1 In the method of converting an existing single deck type floating roof to a double deck type, all parts that penetrate the liquid contact surface of the existing single deck type floating roof are installed while the floating roof is lowered onto the tank bottom plate. After that, water was injected into the tank, the floating roof was raised to the surface, and leakage was confirmed at the lower deck in contact with the liquid surface.Then, the floating roof was raised to the surface and the existing deck plate was held horizontally. A method for modifying a floating roof of a floating roof tank, characterized by assembling an upper deck part with.