JPH0415596Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sealing device for a tank dome of a low-temperature liquefied gas ship, particularly a low-temperature liquefied gas ship that transports low-temperature liquefied gas of -100 degrees Celsius or less.

At the top of the independent rectangular cryogenic tank 1 installed on the cryogenic liquefied gas carrier, a pipe is installed on the deck 3 through the deck opening 2 as shown in Figures 1 to 3, in order to provide a piping passage into the tank. A protruding cylindrical tank dome 4 is provided integrally with the tank, and the deck opening 2 is isolated from the outside world by a flexible sealing device 6 connecting between the dome wall 5 and the deck 3. .

The sealing device 6 usually seals the dome wall 5 and the deck 3.
The members 7 and 8 are fixedly installed in the frame, and the members 7 and 8 are connected using a ring-shaped flexible joint 9 to prevent outside air from entering the hold space 10 and to prevent the hull from deflecting and It is designed to absorb the relative displacement between the tank dome and the hull due to thermal contraction of the tank.

However, due to repeated deformation of the sealing device 6, the seals between the mounting surfaces a and a between the flexible joint 9 and the members 7 and 8 are easily damaged, and atmospheric pressure moisture enters into the hold space 10, causing the cold insulation layer of the low-temperature tank. 11, and there was a risk that the cold insulating layer 11 would be damaged.

The present invention was made to eliminate the above-mentioned drawbacks, and is a tank dome sealing device for airtightly connecting the tank dome that protrudes onto the hull deck through an opening provided in the hull deck and the hull deck. A tank is provided between a flange-shaped upper member fixed to the dome wall and projecting laterally, and a lower member surrounding the opening and having a member fixed on the hull deck and facing the upper member. Two flexible joints that double surround the periphery of the dome and have a flexible part extending in the circumferential direction in the middle part are hermetically adhered to each other.
An airtight ring-shaped hollow part is formed between each flexible joint and the upper and lower members, and dry gas at a pressure slightly higher than atmospheric pressure is filled in the hollow part, and the flexible part of the outer flexible joint is This relates to a sealing device for a tank dome, in which the inner flexible joint is held in a state in which it projects outward in the radial direction of the opening, and a flexible part of the inner flexible joint is held in a state in which it is held in a state in which it projects inward in the radial direction of the opening. This ensures reliable sealing and prevents freezing of the cold insulation layer.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 4 shows an embodiment of the sealing device of the present invention, in which a disc-shaped upper member 21 is fixed to the top of the dome wall 5, and the upper member 21 is fixed to the deck 3 surrounding the deck opening 2. Opposing annular flange 2
2, and two flexible joints 24, 25 of different diameters formed in a ring shape using neoprene-based synthetic rubber, etc., and the flexible joints 24, 25 are arranged around the dome 4. They are arranged almost concentrically, and the upper and lower parts of the outer joints 24 and 25 are hermetically bonded to the mounting members 26 and 26 provided on the upper and lower members as shown in the figure, and if necessary, they can be attached to the machine using a band (not shown) or the like. to be maintained.

Next, the flexible joints 24, 25 and the upper and lower members 21,
In the ring-shaped hollow part 27 formed by 23,
A dry gas, such as nitrogen gas, at a pressure slightly higher than atmospheric pressure is filled. In this way, the upper and lower members 2
Since the two flexible joints 24 and 25 are airtightly bonded between the two flexible joints 24 and 23, there is a gap between the two flexible joints 24 and 25 and the upper and lower members 21 and 23. This reliably prevents dry gas from leaking.

Moreover, the two flexible joints 24 and 25 are heated by the sealed dry gas at a pressure slightly higher than atmospheric pressure.
Since the bent portion of the hollow portion 27 is always maintained in a state protruding outward from the hollow portion 27 regardless of fluctuations in atmospheric pressure, etc.,
The shapes of the flexible joints 24, 25 are stabilized, and airtightness between the two flexible joints 24, 25 and the upper and lower members 21, 23 is maintained.

Therefore, there is no possibility that moist outside air will pass through the sealing device and enter the holding space 10.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

The tank dome sealing device for a low-temperature liquefied gas carrier of the present invention has a structure in which two flexible joints are airtightly bonded between the upper and lower members. It is possible to reliably prevent dry gas from leaking due to a gap between the two flexible joints, and because of the enclosed dry gas at a pressure slightly higher than atmospheric pressure, the flexible portions of the two flexible joints can be connected to atmospheric pressure. Regardless of the fluctuations in the
Airtightness is maintained between each flexible joint and the upper and lower members, thereby preventing freezing of the cold insulation layer and damage due to freezing.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the general arrangement of independent rectangular tanks in a low-temperature liquefied gas carrier, Figure 2 is a cutaway front view of the ship's hull showing the general arrangement of the sealing device of a conventional tank dome, and Figure 3 is the same as in Figure 2. FIG. 4 is a cutaway front view showing an embodiment of the sealing device of the present invention. In the figure, 1 is a low temperature tank, 2 is a deck opening, 3 is a deck, 4 is a tank dome, 5 is a dome wall, 21 is an upper member, 23 is a lower member, 24 and 25 are flexible joints, and 27 is a hollow part shows.

Claims (1)

[Scope of utility model registration request] In a tank dome sealing device for airtightly connecting a tank dome that protrudes onto the hull deck through an opening provided in the hull deck and the hull deck, a flange-like part that is fixed to the dome wall and projects laterally is used. and a lower member that surrounds the opening and is fixedly installed on the hull deck and has a member that faces the upper member, double surrounding the tank dome and extending in the circumferential direction in the middle part. Two flexible joints each having a flexible part are hermetically bonded to form an airtight ring-shaped hollow part between the two flexible joints and the upper and lower members, and atmospheric pressure is applied to the hollow part. Dry gas at a slightly higher pressure is filled in to maintain the flexible portion of the outer flexible joint in a state protruding outward in the radial direction of the opening, and the flexible portion of the inner flexible joint is held in a state that protrudes outward in the radial direction of the opening. A sealing device for a tank dome of a low-temperature liquefied gas carrier, characterized in that the tank dome is held in a state of protruding inward.