JPS5810315B2 - Offshore storage tanks for flammable liquids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a marine storage tank for flammable liquid that is installed floating on the sea.

In recent years, offshore oil stockpiling has been considered with the aim of ensuring a stable and sustainable supply and safe storage of oil, and a candy-shaped tank floating on the sea surface is used as an offshore storage tank for this purpose. Are known.

However, in such conventional offshore storage tanks, the mounting support (the height from the water line to the top of the tank) changes depending on the increase or decrease in the amount of oil in the tank, and the mounting support changes particularly when the amount of oil is low. As the wind load on the tank increases, the oscillation of the tank itself also increases, so it is necessary to increase the capacity of the tank's mooring device.

Also, when the tank is not fully loaded with oil, the space inside the tank is filled with gas, which is dangerous.

This invention has been made in view of the above-mentioned circumstances, and is a flammable liquid that does not change the mounting support due to an increase or decrease in the amount of flammable liquid in the tank, and does not cause the tank to be filled with gas. The purpose is to provide marine storage tanks for liquids.

The present invention will be explained in detail below with reference to embodiments shown in the drawings.

The marine storage tank consists of a tank upper body (first tank body) 1 floating on the sea surface, and a tank lower body (second tank body) 2 fitted into the upper body 1 from below.

The upper body 1 has a top wall 3 and has a bottomless cylindrical shape with an open bottom. An inner circumferential wall 5 having the same height as the outer circumferential wall 4 is formed inside the outer circumferential wall 4, and an inner petroleum storage chamber (flammable liquid storage chamber) 6 and an outer annular buoyancy chamber 7.

An oil supply/discharge pipe 8 and an air vent pipe 9 with valves are provided in the upper part of the storage chamber 6, and an air supply/discharge pipe 10 is provided in the upper part of the buoyancy chamber 7.

The upper body 1 is moored by appropriate means so that its upper end slightly protrudes above the sea surface.

The lower body 2 has a double cylindrical shape in which a bottomless cylindrical buoyancy chamber 12 with a top wall 11 is surrounded by an annular chamber 13 with an open top. The outer circumferential wall 14 of the annular chamber 13 is fitted into the buoyancy chamber 7 of the upper body 1 and is movable up and down, forming the bottom of the oil storage chamber 6.

The buoyancy chamber 12 of the lower body 2 is provided with an air supply/discharge pipe 15 with a valve.

Further, the upper and lower main bodies 12 are provided with stoppers (paths shown) for preventing the lower main body 2 from falling.

In the above, a predetermined amount of air is always kept in the buoyancy chamber 7 of the upper body 1, and this air layer separates the oil inside the outer circumferential wall 14 of the lower body 2 from the seawater outside. They do not touch or mix with each other.

Although not shown, the upper body 1 is provided with a level detector for seawater that has entered the buoyancy chamber γ, and the amount of air in the buoyancy chamber 7 is adjusted based on this signal.

In addition, the storage chamber 6 is always filled only with oil, and when the amount of oil in the storage chamber 6 increases, the lower body 2 is pushed down against buoyancy, and the amount of oil in the storage chamber 6 decreases. The buoyancy of the lower body 2 is then adjusted so that the lower body 2 moves upward due to the buoyancy.

Therefore, even if the amount of oil in the storage chamber 6 changes, the upper main body 1 hardly moves up and down, and furthermore, the storage chamber 6 is never filled with gas.

The shapes of the two tank bodies can be changed as appropriate; for example, they may be rectangular when viewed from above.

Furthermore, a plurality of sets of storage chambers and buoyancy tanks may be formed in the first tank body, and a plurality of second tank bodies may be fitted into these sets, respectively.

The marine storage tank according to the present invention has an annular buoyancy chamber 7 with an open bottom surrounding a flammable liquid storage chamber 6 with an open bottom.
An annular chamber 13 having an open top is formed around a first tank body 1 floating on the sea surface and a buoyancy chamber 12 having a top wall 11. It is fitted into the storage chamber 6 of the tank body 1, and
The outer circumferential wall 14 of the annular chamber 13 is fitted into the buoyancy chamber γ of the first tank body 1, and the second tank body 2 forms the bottom of the storage chamber 6. When the amount of flammable liquid increases, the second tank body 2 is pushed down against buoyancy, and when the amount of flammable liquid in the storage chamber 6 decreases, the second tank body 2 is pushed upward due to buoyancy. As a result, the storage chamber 6 is filled with only the flammable liquid, so that the load does not change due to an increase or decrease in the amount of flammable liquid in the tank, and the gas in the tank does not change. It is not full.

Therefore, by setting the support to be small in advance, it is possible to reduce the wind load that the tank receives and downsize the mooring device.

In addition, due to the air in the buoyancy chamber 7 of the first tank body 1,
Since the flammable liquid in the storage chamber 6 and the seawater outside can be separated, the flammable liquid and seawater do not come into contact with or mix with each other.

[Brief explanation of the drawing]

The drawing is a vertical sectional view showing an embodiment of the invention. 1... Tank upper body (first tank body), 2... Tank lower body (second tank body), 6... Oil storage chamber (flammable liquid storage chamber), 7... Buoyancy chamber, 11... ...Top wall,
12 buoyancy chamber, 13... annular chamber, 14... peripheral wall.

Claims (1)

[Claims] 1 An annular buoyancy chamber 7 with an open bottom is formed around a combustible liquid storage chamber 6 with an open bottom, and a buoyancy chamber 12 with a first tank body 1 floating on the sea surface and a top wall 11 An annular chamber 13 with an open top is formed around the
In addition, the buoyancy chamber 12 is fitted into the storage chamber 6 of the first tank body 1, and the outer circumferential wall 14 of the annular chamber 13 is fitted into the buoyancy chamber 7 of the first tank body 1, so that the buoyancy chamber 12 is fitted into the storage chamber 6 of the first tank body 1. When the amount of flammable liquid in the storage chamber 6 increases, the second tank body 2 is pushed down against buoyancy, and the storage chamber 6
When the amount of flammable liquid in the second tank body 2 decreases, the second tank body 2
A marine storage tank for flammable liquid, in which the liquid is moved upward by buoyancy, so that the storage chamber 6 is filled only with flammable liquid.