KR20200042103A - Cover for gas dome of liquefied gas cargo - Google Patents

Abstract

The present invention provides a cover for a gas dome of a liquefied gas cargo hold which includes: a cover main body surrounding a lower opening structure of the gas dome installed on a ceiling of the liquefied gas cargo hold of a carrier; a plurality of support shaft parts connected between a floor surface of the cover main body and the bottom of the lower opening structure of the gas dome; and a plurality of inner protruding parts protruding from an inner surface of the cover main body and spaced apart in a height direction of the cover main body. In the cover main body, a plurality of gas holes are formed for introduction or discharge of gas with respect to the liquefied gas cargo hold or collection of the gas generated in the liquefied gas cargo hold.

Description

Gas dome cover for liquefied gas cargo hold {COVER FOR GAS DOME OF LIQUEFIED GAS CARGO}

The present invention relates to a gas dome cover of a liquefied gas cargo hold.

Generally, liquefied gas is stored and transported in a liquefied gas transport ship in a liquefied state through the sea.

For example, liquefied gas is liquefied natural gas (Liquefied Natural Gas: LNG) or liquefied petroleum gas (Liquefied Petroleum Gas: LPG).

In particular, liquefied natural gas is obtained by cooling natural gas to a very low temperature, for example, about -163 ° C, and its volume is reduced to about one-half of that of natural gas in a gas state, and may be suitable for long-distance transportation through the sea.

The liquefied gas transport ship is equipped with a liquefied gas cargo hold including a plurality of liquefied gas storage tanks.

For example, the liquefied gas storage tank is classified into an independent tank type and a membrane type for each standard in order to store liquefied gas such as LNG in a cryogenic state, and the independent tank type storage tank is a MOSS type. It is divided into IHI-SPB type, and membrane type storage tanks include GTT NO 96 type and Mark III type.

In addition, a liquefied gas storage tank is provided with a pump tower, a liquid dome, a gas dome, etc. for the unloading of liquefied gas.

The gas dome of a liquefied gas cargo hold according to the prior art is an inerting process in which an inert gas such as nitrogen gas is injected into a liquefied gas storage tank to prevent the formation of an explosive mixture, or gasing to replace the inert gas with evaporated natural gas It is used for gassing up, or used as a recovery point for boil-off gas (BOG).

In particular, the BOG is compressed by a BOG compressor or pump through a gas dome into a reliquefaction system, and cooled and liquefied in a heat exchanger of the reliquefaction system, and then returned to the liquefied gas storage tank.

If the pump that pressurizes the BOG in the re-liquefaction system operates in an inoperative or abnormal state, the BOG itself is at risk of explosion, and therefore, a means to prevent the pump from malfunctioning is urgent.

For example, when the liquefied gas transport ship is placed under extreme environmental conditions, intense sloshing occurs inside the liquefied gas storage tank, and as a result, the liquefied gas in the liquefied state directly contacts the gas dome or the gas dome. It can be introduced into the interior.

That is, in the state where the sloshing occurs or the liquefied gas is filled in the storage tank of the liquefied gas transport ship under high filling conditions, when the transport ship moves, a suction of the pump is performed to process the BOG. At this time, due to the liquefied gas contacted with the gas dome or introduced into the gas dome, there is a problem that a malfunction of the pump occurs.

According to the technical specifications of the BOG treatment pump of the liquefied gas storage tank according to the prior art, the pump can withstand for a very short time, but after that, it may malfunction or become inoperable, so that the BOG can be properly processed in time. There is no need to incinerate in order to prevent an increase in the internal pressure of the liquefied gas storage tank, and a problem that needs to be sent to another surplus gas treatment means may arise, so there is an urgent need for a means to solve this problem.

In the present invention, by providing a breathable cover body that can cover the lower opening structure of the gas dome, while preventing the liquid liquefied gas from directly flowing into the interior space of the gas dome, various gases in the gas phase (for example, dry gas , It can allow the flow of inert gas, evaporated natural gas, BOG, etc. and prevent malfunction of the pump installed on the path from the gas dome to the gas treatment system (e.g., re-liquefaction system or gas filling system). It is intended to provide a gas dome cover for a liquefied gas cargo hold.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description. Will be able to.

In order to solve the problems as described above, the present invention, the cover body surrounding the lower opening structure of the gas dome installed on the ceiling of the liquefied gas cargo hold of the carrier; A plurality of support shaft portions connected between the bottom surface of the cover body and the bottom surface of the lower open structure of the gas dome; And a plurality of internal protrusions installed to protrude from the inner surface of the cover body and spaced apart in the height direction of the cover body, including, entering or discharging gas into the liquefied gas cargo hold, or in the liquefied gas cargo hold. In order to collect the gas generated in the cover body, a gas dome cover of a liquefied gas cargo hold in which a plurality of gas holes are formed may be provided on the cover body.

In addition, the cover body, a cantilever-shaped bracket portion provided in a plurality on the inner surface of the cover body based on the position spaced upward from the inner projection; And an inner plate of the gas dome supported by the bracket so as to be disposed in the inner space of the cover body in a non-contact state to the pipe end, and having a relatively narrow size compared to the planar area of the cover body. have.

In addition, the cover body, the bottom plate having a relatively larger area than the pipe diameter of the gas dome; A wall portion connected to the edge of the bottom plate, erected vertically from the edge of the bottom plate, and having a height extending to an outer circumferential surface of a pipe end of the gas dome; A ring-shaped upper plate connecting the upper end of the wall portion and the outer circumferential surface of the gas dome to each other; And a plurality of reinforcing ribs installed at a corner position between the top plate and the wall part or at a corner position between the bottom plate and the wall part.

In addition, a drain portion connecting the inner space of the cover body and the inner space of the liquefied gas cargo hold may be further installed on the bottom plate of the cover body.

In addition, the cover body or the inner plate may be made of a breathable plate material having a plurality of vent holes by performing laser micro hole processing on the plate material of the material.

According to the gas dome cover of the liquefied gas cargo hold according to an embodiment of the present invention, there is an effect of preventing the malfunction of the pump for pumping various gases processed through the gas dome.

In addition, the gas dome cover of the liquefied gas cargo hold according to an embodiment of the present invention has the advantage of saving the pump maintenance and maintenance time by preventing the malfunction or failure of the pump in advance.

In addition, since the gas dome cover of the liquefied gas cargo hold according to the embodiment of the present invention is made of a breathable material, gas flow is allowed in both directions from the inside of the cover to the outside of the cover or from the outside of the cover to the inside of the cover, but in the liquefied gas storage tank. By preventing the liquefied liquefied gas from directly flowing into the inner space of the gas dome, there is an advantage of preventing a malfunction of a related system in which a pump is installed while performing a gas collection function and a gas diffusion function.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description. will be.

1 is a perspective view of a gas dome cover of a liquefied gas cargo hold according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of the gas dome cover shown in FIG. 1 to illustrate a coupling relationship between the gas dome and the lower open structure.
3 is a view showing the installation state of the gas dome cover shown in Figure 1 for the liquefied gas cargo hold.
4 is an enlarged sectional view of circle A shown in FIG. 3.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION The detailed description set forth below, in conjunction with the accompanying drawings, is intended to describe exemplary embodiments of the invention, and is not intended to represent the only embodiments in which the invention may be practiced.

In order to clearly describe the present invention in the drawings, parts irrelevant to the description may be omitted, and the same reference numerals may be used for the same or similar elements throughout the specification.

In the drawing, FIG. 1 is a perspective view of a gas dome cover of a liquefied gas cargo hold according to an embodiment of the present invention, and FIG. 2 is a gas dome shown in FIG. 1 to illustrate a coupling relationship with the lower open structure of the gas dome It is an exploded perspective view of the cover.

1 and 2, the gas dome cover 10 of the liquefied gas cargo hold according to the present embodiment is capable of inflow and outflow of gas processed through the gas dome 1, but the liquefied gas cargo hold (3) ( (See FIG. 3) Due to the internal sloshing or high filling conditions for liquefied gas in the liquefied gas cargo hold 3, due to the liquid liquefied gas around the gas dome 1, the gas dome 1 ) Can be responsible for preventing the malfunction or inoperability of the pump (not shown) connected to.

As an example for this, the gas dome cover 10 of the liquefied gas cargo hold may include a cover body 100, a support shaft part 200, an inner protrusion part 300, a bracket part 400, and an inner plate 500. .

Connection and coupling of each component including the cover body 100, the support shaft portion 200, the inner protrusion portion 300, the bracket portion 400, and the inner plate 500 may be performed by welding or the like.

At this time, the connection or assembly of the cover body 100, the support shaft portion 200, the inner protrusion portion 300, the bracket portion 400, the inner plate 500, etc., while considering assembly interference or tolerance, lower opening structure ( It can be used in parallel when connecting and assembling the components of 2).

In addition, the support shaft part 200 and the bracket part 400 may be connected to the inner surface of the cover body 100 or to other parts (for example, the bottom surface of the gas diffusion plate 2b or the bottom surface of the inner plate 500). At this time, expansion plates 210 and 410 may be further interposed in the end portion for welding connection, such as the support shaft portion 200, to expand the welding area.

The cover body 100 may serve to surround the lower opening structure 2 of the gas dome 1 installed on the ceiling of the liquefied gas cargo hold of the carrier.

More specifically, the cover body 100 may include a bottom plate 110, a wall portion 120, a top plate 130 and a reinforcing rib 140.

The bottom plate 110 may have a relatively large area than the pipe diameter of the gas dome 1.

The wall part 120 may be connected to an edge of the bottom plate 110, that is, an outer diameter portion of the bottom plate 110.

The wall portion 120 is vertically erected from the edge of the bottom plate 110, and may have a height extending to the outer circumferential surface of the pipe end of the gas dome 1.

The top plate 130 may refer to a ring-shaped plate member or a finishing plate to connect the upper end portion of the wall portion 120 and the outer circumferential surface of the gas dome 1 to each other.

Here, the inner diameter portion of the top plate 130 may be connected to the outer peripheral surface of the pipe of the gas dome 1 by welding.

The reinforcing ribs 140 may be installed in a plurality of corner positions between the top plate 130 and the wall part 120 or a corner position between the bottom plate and the wall part.

The reinforcing ribs 140 may increase the durability and structural rigidity of the cover body 100, and may serve to protect the cover body 100 from external forces due to sloshing.

The gas dome 1, which is the object of application of the cover body 100, may refer to a pipe passing through the wall of the liquefied gas cargo hold 3.

That is, the pipe end 1a of the gas dome 1 protrudes through the ceiling of the liquefied gas cargo hold 3.

In addition, the lower opening structure 2 is coupled to the pipe end 1a of the gas dome 1.

Here, the lower opening structure (2) of the gas dome (1) of the pipe end (1a) of a plurality of spaced apart along the circumferential direction (for example, four) of the extension bar (2a), and the extension bar (2a) of The gas diffusion plate 2b connected to the end, and the upper surface of the gas diffusion plate 2b may be formed of a cross-shaped reinforcement 2c that reinforces and connects the extension bars 2a facing each other in a spaced apart state.

The lower opening structure (2) through the opening (2d) between the extension bar (2a), the gas in the gaseous state (e.g., gaseous phase) to be processed in the liquefied gas cargo hold (1), such as dry gas, inert gas, evaporation Natural gas, BOG, etc.) can flow.

In addition, various gases supplied from the outside flow relatively freely from the inner space of the gas dome 1 through the opening 2d toward the inner space of the liquefied gas cargo hold 3, at this time being guided by the gas diffusion plate 2b, , It can be spread along the ceiling surface of the liquefied gas cargo hold (3).

In addition, various gases present in the interior space of the liquefied gas cargo hold 3 can also be freely introduced into the interior space of the gas dome 1 through the opening 2d.

If the gas dome cover 10 of the liquefied gas cargo hold of the present embodiment is not applied, as described above, in a high filling condition of liquefied gas or a sloshing situation, the liquefied gas hold 3 Liquefied gas in a liquid state (eg, liquid) that has reached the gas dome 1 or the lower open structure 2 based on the internal space of the gas also easily flows into the internal space of the gas dome 1 through the opening 2d. This may result in malfunction or inoperability of the pump (not shown) associated with the gas dome 1.

However, in the case where the gas dome cover 10 of the liquefied gas cargo hold of the present embodiment is applied, a plurality of gas holes 121 may be formed in the cover body 100.

In addition, through a design change, the cover body 100 is provided with a plurality of vent holes made of a breathable material capable of passing gaseous liquefied gas and impregnating liquid liquefied gas by selecting and processing materials as described below. It may be formed.

Further, each gas hole 121 may also be covered by a porous plate (not shown) having a plurality of vent holes.

In addition, the diameter and number of the gas holes 121 may be determined through a gas flow rate, a flow rate, and the like, and thus may not be limited to specific values.

In addition, the cover body 100 is closed by a bottom plate 110 such as a disk shape and a ring-shaped top plate 130 as a box structure as described later.

Here, the plurality of gas holes 121 are disposed on the upper side of the cover body 100, which is a position where liquid liquefied gas does not reach even in a high filling condition or a slotting situation, so that the liquefied gas cargo hold ( 3) Entry or discharge of gas to or liquefied gas smoothly captures gas (eg, BOG) generated in the cargo hold 3, but liquefied liquefied gas is easily introduced into the interior of the cover body 100 It is possible to prevent, and as a result, an effect capable of preventing a malfunction of the pump and the like in advance.

That is, the cover body 100 may act as a barrier to suppress the flow of liquid liquefied gas with respect to the opening 2d of the lower opening structure 2 of the gas dome 1.

The plurality of support shaft parts 200 include the bottom surface of the cover body 100 (eg, the top surface of the bottom plate 110 of the cover body 100) and the bottom surface of the lower opening structure 2 of the gas dome 1 (eg : The bottom surface of the gas diffusion plate 2b).

The plurality of support shaft portions 200 serve to increase the structural durability of the cover body 100 based on the bottom surface of the lower open structure 2 of the gas dome 1 and the gas diffusion plate of the lower open structure 2 ( 2b) and between the bottom plate 110 of the cover body 100 may serve to secure the temporary liquid storage chamber 111 (see FIG. 4).

That is, the case where the liquefied gas of the liquid flows into the inside of the cover body 100 via the gas hole 121 may be very rare.

However, even in this case, since the fluid passage area of the gas hole 121 is significantly smaller than the fluid passage area of the opening 2d of the lower opening structure 2 of the gas dome 1, it may be relatively very small amount. Only the liquefied gas in the liquid can flow into and fall into the interior of the cover body 100.

In this case, the liquefied gas of the liquid that can fall through the gas hole 121 is collected toward the temporary liquid storage chamber 111 between the aforementioned gas diffusion plate 2b and the bottom plate 110 of the cover body 100. As a result, it can be forbidden that the liquefied gas of the liquid flows directly into the inner space of the gas dome 1.

That is, the liquid flow of the temporary liquid storage chamber that can face the gas dome 1 is primarily blocked by the gas diffusion plate 2b, and the gas dome (secondly) by the inner plate 500 to be described later The liquid flow in the central region of the pipe of 1) can be blocked.

In addition, the liquid flow of the temporary liquid storage chamber 111 that can face the gas dome 1 may be made along the inner surface of the cover body 100, depending on the case such as sloshing or excessive ship movement, but the cover body An effect that can also be blocked by the inner protrusion 300 protruding from the inner surface of (100) can be exhibited.

To this end, a plurality of inner protrusions 300 are installed to protrude from the inner surface of the cover body 100 (eg, the inner surface of the wall portion 120 of the cover body 100), and the cover body 100 of the It may be spaced apart in the height direction.

Each inner protrusion 300 may have a cross-sectional shape of a Hangul translator or Nieunja.

For example, each inner protrusion 300 connects a bent portion 310 having a ring-shaped Hangul translator or a Ni Eunja cross-section shape, and the bent portion 310 to the inner surface of the wall portion 120 of the cover body 100 It may be made of a ring-shaped adapter portion 320 to make.

At this time, the end portion of the bent portion 310 is directed downward.

In addition, when adjusting the flow path of the liquid liquefied gas, the height of the bent portion 310 protruding based on the inner surface of the adapter portion 320 may be determined differently, and the bent shapes may be the same or different. As it may, it may not be limited to a specific cross-sectional shape.

However, as an example, the cross-sectional shape of the Hangul translator or the Ni Eunja of each inner protrusion 300 extends in the horizontal direction along the inner surface of the wall portion 120 of the cover body 100, so that each inner protrusion 300 is Each may be a closed loop structure.

Here, the adapter portion 320 of each inner protrusion 300 may be connected to the inner surface of the wall portion 120 of the cover body 100 by either welding or welding or a conventional structure attachment method.

Therefore, due to the geometric features of each inner protrusion 300 (eg, the end of the bent portion 310 faces downward), the liquid flow of the liquefied gas of the liquid downwards along the surface of the inner protrusion 300. It can flow relatively easily.

In addition, the liquefied gas of the liquid formed at the end of the bent portion 310 of the inner protruding portion 300 may be directly dropped toward the bottom plate of the cover body 100.

On the other hand, the liquid flow in the upward direction (for example, direction toward the gas dome 1) due to external force such as sloshing and hull movement is a bent portion 310 of a plurality of inner protrusions 300 that serve as a preventive or engaging jaw. It can be blocked by being blocked.

That is, since each internal protrusion 300 suppresses upward liquid flow, and the liquid liquefied gas hits the surface of each internal protrusion 300 and is likely to change into a gas phase, at least the liquid liquefied gas is directly As it can exhibit a superior effect that can be prevented from entering the interior of the gas dome (1).

 Meanwhile, the bracket body 400 and the inner plate 500 may be further coupled to the cover body 100.

Here, the bracket 400 is a plurality of the inner surface of the cover body 100 based on the position spaced upward from the inner protrusion 300 (for example, the inner surface of the wall portion 120 of the cover body 100) It is installed, and may be formed in a cantilevered shape, so as to each serve as a stand.

The bracket parts 400 may be arranged radially to face the center of the cover body 100, respectively.

The object to be supported or the object to be supported by the bracket 400 may be an inner plate 500 to be positioned at the center of the cover body 100.

The inner plate 500 has a diameter smaller than the inner diameter of the pipe end 1a of the gas dome 1 to cover the flow of the gas dome 1 while allowing gas flow, or the cover body 100 It may be manufactured to have a relatively narrow size compared to the plane area of.

For example, the inner plate 500 is disposed in the inner space of the cover body 100 in a non-contact state to the pipe end 1a of the gas dome 1 and can be supported by the aforementioned bracket part 400. .

That is, gas flow may be possible through a space between the outer diameter portion of the inner plate 500 and the inner diameter of the pipe end 1a of the gas dome 1.

On the other hand, the bottom plate 110 of the cover body 100 may be further provided with a drain unit 150 that connects the internal space of the cover body 100 and the internal space of the liquefied gas cargo hold 3 to each other.

The drain unit 150 may be coupled to the bottom plate 110 by a normal pipe through installation method using a straight pipe or a curved pipe.

At this time, the upper portion of the drain portion 150 protrudes relative to the top surface of the bottom plate 110, or a predetermined protruding height h (for example, the height of the liquid liquefied gas in the interior of the temporary liquid storage chamber 111) ).

In this case, even if the water surface of the liquid liquefied gas in the cargo hold 3 contacts the bottom surface of the cover body 100 or rises slightly higher to lock the bottom surface of the cover body 100, the liquid liquefied gas is a drain part ( 150) only partially enters the interior space, there is an effect that may not be introduced into the interior of the cover body 100.

Then, by sloshing or the like, the liquid liquefied gas passes through the gas hole 121 and enters the temporary liquid storage chamber 111, and thereafter, the height of the water surface in the temporary liquid storage chamber 111 is the drain portion ( When the projecting height (h) of the upper portion of 150) or more, the liquid liquefied gas may be discharged to the outside of the cover body 100 via the drain unit 150.

The diameter of the drain portion 150 may be selectively determined within a range sufficient to sufficiently achieve the purpose of drain while suppressing inflow to the maximum by sloshing.

3 is a view showing the installation state of the gas dome cover shown in FIG. 1 for a liquefied gas cargo hold, and FIG. 4 is an enlarged cross-sectional view of circle A shown in FIG. 3.

3 and 4, the plurality of gas holes 121 of the cover body 100 is lower than the installation height of the inner plate 500, and the bottom surface of the lower opening structure 2 of the gas dome 1 (eg : Based on any one position selected within a range between the gas diffusion plate (2b) higher than the bottom surface, the wall portion 120 to penetrate through the wall thickness direction of the wall portion 120 of the cover body 100 Is formed on.

At this time, the plurality of gas holes 121 are disposed at an installation height equivalent to the bracket 400 based on the bottom plate 110 of the cover body 100.

In addition, the gas holes 121 may be spaced apart in the horizontal direction of the cover body 100 to increase gas diffusion performance.

In addition, the cover body 100, the support shaft portion 200, the inner protrusion portion 300, the bracket portion 400 and the inner plate 500 are made of stainless steel, aluminum alloy material for the barrier of the liquefied gas cargo hold, invar Material, may be formed of any one of 9% nickel steel material.

In particular, the cover body 100 is a box structure made of a plate material of the above-mentioned material, and may have any one of a cylindrical shape, a hexahedral shape, and a polyhedron shape. Gas flow is possible, but durability is minimized while minimizing liquid flow. If it can be secured, it need not be limited to a specific shape.

On the other hand, the cover body 100 and / or the inner plate 500, while allowing a smoother gas flow in the normal, to minimize the liquid flow, to perform a laser micro-hole processing on a plate material of the aforementioned material to a plurality of It may be made of a breathable plate with vent holes.

Here, the diameter of each of the vent holes by laser micro hole processing may be determined to a value within a range of several tens of micrometers or more and 1 millimeter or less, however, it is possible to pass liquefied gas in the gas phase, but to pass the liquefied gas in the liquid phase. When a condition that can be suppressed as much as possible is satisfied, it may not be limited to a specific value, such as any one selected from within the above range.

Therefore, when the liquid liquefied gas is in a sloshing or high filling condition, it is a degree that a small amount penetrates into the inside of the cover body 100 through a plurality of vent holes, so that the purpose of preventing a pump malfunction can be sufficiently achieved. There is this.

As described above, in the gas dome cover of the liquefied gas cargo hold according to the present embodiment, when the liquefied gas hold 3 is of a membrane type, there are difficulties in installing a membrane barrier when attaching an adjunct to the cargo hold 3, As described above, by being installed based on the pipe of the gas dome 1, there is an advantage that can solve the problem of the cover installation.

In addition, the gas dome cover of the liquefied gas cargo hold according to the present embodiment is provided with an inner protrusion 300 on the inner surface of the cover body 100 to suppress possible liquid flow along the inner surface of the cover body 100. In addition, it is also possible to suppress the liquefied gas from flowing into the inner space of the pipe of the gas dome 1 through the inner plate 500, as a result, it is possible to prevent the existing pump malfunction or inoperability in advance. , There is an advantage that can keep the pump suction efficiency stable.

The embodiments of the present invention disclosed in the present specification and drawings are merely intended to easily describe the technical contents of the present invention and to provide specific examples to help understanding of the present invention, and are not intended to limit the scope of the present invention.

Therefore, the scope of the present invention should be construed as including all the modified or modified forms derived on the basis of the technical spirit of the present invention in addition to the embodiments disclosed herein.

10: gas dome cover of liquefied gas cargo hold 100: cover body
200: support shaft 300: inner projection
400: bracket 500: inner plate

Claims (5)

A cover body surrounding the lower opening structure of the gas dome installed on the ceiling of the liquefied gas cargo hold of the carrier;
A plurality of support shaft portions connected between the bottom surface of the cover body and the bottom surface of the lower open structure of the gas dome; And
Includes; is provided to protrude from the inner surface of the cover body, spaced apart in the height direction of the cover body;
In order to enter or discharge gas to the liquefied gas cargo hold, or to collect the gas generated in the liquefied gas hold, the cover body has a gas dome cover in the liquefied gas hold. According to claim 1,
The cover body,
A cantilever-shaped bracket portion provided in plural on the inner surface of the cover body based on a position spaced upward from the inner protrusion; And
Liquefied gas in which the inner plate of the cover body is supported by the bracket portion and is relatively narrow compared to the planar surface of the cover body so as to be disposed in the inner space of the cover body in a non-contact state to the pipe end of the gas dome. Gas dome cover in cargo hold. According to claim 2,
The cover body,
A bottom plate having a relatively larger area than the pipe diameter of the gas dome;
A wall portion connected to the edge of the bottom plate, erected vertically from the edge of the bottom plate, and having a height extending to an outer circumferential surface of a pipe end of the gas dome;
A ring-shaped upper plate connecting the upper end of the wall portion and the outer circumferential surface of the gas dome to each other; And
A gas dome cover of a liquefied gas cargo compartment comprising; a plurality of reinforcing ribs installed at a corner position between the top plate and the wall part or a corner position between the bottom plate and the wall part. The method of claim 3,
On the bottom plate of the cover body,
The gas dome cover of the liquefied gas cargo hold is further provided with a drain portion connecting the inner space of the cover body and the inner space of the liquefied gas hold. According to claim 2,
The cover body or the inner plate,
Gas dome cover of a liquefied gas cargo hold made of a breathable plate with a plurality of vent holes by performing laser micro hole processing on the plate of the above material.

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