阅读说明：本技术 液化气贮存罐及船舶 (Liquefied gas storage tank and ship ) 是由 上田伸 于 2020-02-17 设计创作，主要内容包括：液化气贮存罐具备：容器主体(60),在内部贮存液化气,并具有能够应对至比容器主体(60)所设置的位置处的大气压大的压力的设计压力；导出配管(63),遍及容器主体(60)的内外地设置,一端在容器主体(60)的内部在液化气的液相(L)中开口,另一端配置于容器主体(60)的外部,并在内部形成液化气的导出流路(64)；及连通部(65),能够将容器主体(60)的内部的液化气的气相(L)存在的位置与导出流路(64)连通。(A liquefied gas storage tank is provided with: a container body (60) that stores liquefied gas therein and has a design pressure that can handle a pressure greater than the atmospheric pressure at a location where the container body (60) is disposed; a lead-out pipe (63) which is provided inside and outside the container body (60), has one end opening into the liquid phase (L) of the liquefied gas inside the container body (60), has the other end disposed outside the container body (60), and has a lead-out flow path (64) for the liquefied gas formed inside; and a communication section (65) that can communicate the position where the gas phase (L) of the liquefied gas is present inside the container body (60) with the delivery flow path (64).)

1. A liquefied gas storage tank is provided with:

a container main body that stores liquefied gas therein and has a design pressure that can cope with a pressure greater than atmospheric pressure at a position where the container main body is provided;

a lead-out pipe that is provided inside and outside the container body, has one end that opens into a liquid phase of the liquefied gas inside the container body, has the other end that is disposed outside the container body, and has a lead-out flow path for the liquefied gas inside; and

and a communication section capable of communicating a position in which the gas phase of the liquefied gas is present in the container body with the lead-out flow path.

2. A liquefied gas storage tank according to claim 1,

the communicating portion is a connecting pipe that connects a position of the container main body where the gas phase of the liquefied gas is present to the lead-out pipe outside the container main body and forms a connecting flow path inside the connecting pipe,

the liquefied gas storage tank further includes an on-off valve provided in the connection pipe and capable of opening and closing the connection passage.

3. A liquefied gas storage tank according to claim 2,

the on-off valve is a three-way valve that is provided so as to be switchable between a first state in which the lead-out flow path is communicated between the one end and the other end of the lead-out pipe and the connection flow path is closed, and a second state in which the connection flow path is opened by communicating the one end of the lead-out pipe with the connection flow path via the lead-out flow path.

4. A liquefied gas storage tank according to claim 2 or 3,

the liquefied gas storage tank further includes a control device that opens and closes the connection flow path by the opening and closing valve,

the control device closes the connection passage by the open/close valve when the liquefied gas is led out from the container body through the lead-out passage.

5. A liquefied gas storage tank according to claim 1,

the communicating portion is a communicating hole provided in the delivery pipe so as to communicate a position where the gas phase of the liquefied gas is present with the delivery flow path in the container main body.

6. A liquefied gas storage tank according to any one of claims 1 to 5,

the liquefied gas storage tank further includes:

an atmosphere opening pipe provided in the container main body and capable of communicating a position where the gas phase of the liquefied gas is present with the outside of the container main body; and

and a valve capable of opening and closing a flow path inside the atmosphere opening pipe.

7. A ship is provided with:

a liquefied gas storage tank as claimed in any one of claims 1 to 6.

Technical Field

The present invention relates to a liquefied gas storage tank and a ship equipped with the liquefied gas storage tank.

The present application claims priority to japanese patent application No. 2019 @ 81680, filed on 23/4/2019, and the contents of which are incorporated herein by reference.

Background

Tanks for storing liquefied gas such as LNG or LPG are generally known. The liquefied gas stored in the tank is used as a fuel in a thermal power plant or as a raw material for city gas.

A ship equipped with such a tank is also known (for example, patent document 1). A pump is provided inside such a tank, and the liquefied gas in the tank is transported to a main engine through a pipe and used as fuel for a ship.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2018-176900

Disclosure of Invention

Problems to be solved by the invention

However, there are cases where: for example, the liquefied gas evaporates in the tank due to the tank being heated by outside air, and the pressure inside the tank becomes higher than atmospheric pressure. In such a case, for example, when a failure occurs in the pipe due to a failure of a gasket of a valve provided in the pipe for taking out the liquefied gas in the tank to the outside of the tank, a failure of welding of the pipe, or the like, and the pipe opens into the atmosphere in the middle of the pipe, the liquefied gas is pushed out by a pressure difference between the pressure in the tank and the atmospheric pressure, and leakage of the liquefied gas cannot be prevented, and a large amount of liquefied gas may leak. In particular, in a medium-and small-sized tank having a large design pressure (pressure resistance), the differential pressure between the pressure in the tank and the atmospheric pressure is large, and the leakage amount of liquefied gas is large.

Further, when the leakage amount of the liquefied gas is large, a drip plate for receiving the leaked liquefied gas needs to be large, which leads to an increase in cost.

Therefore, the present invention provides a liquefied gas storage tank and a ship capable of suppressing leakage of liquefied gas with a simple structure.

Means for solving the problems

A liquefied gas storage tank according to a first aspect of the present invention includes: a container main body that stores liquefied gas therein and has a design pressure that can be applied to a pressure greater than atmospheric pressure at a position where the container main body is provided; a lead-out pipe which is provided inside and outside the container body, has one end opening into the liquid phase of the liquefied gas inside the container body and the other end disposed outside the container body, and forms a lead-out flow path for the liquefied gas inside the container body; and a communicating portion capable of communicating a position in which the gas phase of the liquefied gas is present in the container body with the lead-out flow path.

In such a storage tank, if a failure occurs in the lead-out pipe outside the container body and the lead-out flow path is opened to the atmosphere in the middle thereof, when the pressure in the container body becomes higher than the atmospheric pressure due to evaporation of the liquefied gas, the liquid phase of the liquefied gas is pushed out to the outside of the container body by the pressure difference between the atmospheric pressure and the pressure inside the container body and leaks. In this aspect, even in such a case, the pressure of the lead-out flow path can be made equal to the pressure of the gas phase of the liquefied gas by communicating the gas phase of the liquefied gas with the lead-out flow path by the communication portion. As a result, the pressure inside the container body can be equalized to the pressure in the lead-out flow path, and it is possible to avoid a situation in which the liquid phase of the liquefied gas is pushed out to the outside of the container body and the leakage of the liquefied gas cannot be stopped.

In the liquefied gas storage tank, the communication portion may be a connection pipe that connects a position outside the container body where the gas phase of the liquefied gas in the container body exists to the lead-out pipe and forms a connection flow path inside, and the liquefied gas storage tank may further include an opening/closing valve that is provided in the connection pipe and that can open/close the connection flow path.

By providing the connection pipe as the communication portion and opening the connection flow path of the connection pipe with the opening/closing valve, even if a trouble occurs in the lead-out pipe outside the container body and the lead-out flow path is opened to the atmosphere in the middle thereof, the pressure of the lead-out flow path can be equalized to the pressure of the gas phase of the liquefied gas by flowing the gas phase of the liquefied gas into the lead-out flow path through the connection flow path of the connection pipe. As a result, it is possible to avoid a situation in which the liquid phase of the liquefied gas is pushed out of the container body by the pressure difference between the atmospheric pressure and the pressure inside the container body, and the leakage of the liquefied gas cannot be stopped. Further, it is possible to avoid a situation in which the liquid phase of the liquefied gas flows into the connection flow path during normal operation in which the connection flow path is closed by the open/close valve and a trouble does not occur in the lead-out pipe, and it is possible to reduce flow loss in a situation in which the liquid phase of the liquefied gas is led out to the outside of the container body through the lead-out pipe.

In the liquefied gas storage tank, the opening/closing valve may be a three-way valve that is provided so as to be switchable between a first state in which the lead-out flow path is closed while the lead-out flow path is communicated between the one end and the other end of the lead-out pipe, and a second state in which the connection flow path is opened by communicating the one end of the lead-out pipe with the connection flow path via the lead-out flow path.

In this case, the function of opening and closing the connection flow path and the function of opening and closing the lead-out flow path can be combined by one three-way valve, and there is no need to provide a valve for opening and closing the connection flow path and a valve for opening and closing the lead-out flow path separately, which leads to cost reduction and space saving.

The liquefied gas storage tank may further include a control device that opens and closes the connection flow path by the opening and closing valve, and the control device may close the connection flow path by the opening and closing valve when the liquefied gas is led out from the container body through the lead-out flow path.

Even if a failure occurs in the lead-out pipe outside the container body and liquefied gas leaks from the lead-out passage, if the connection passage is opened by the open/close valve at normal times, it is possible to avoid a situation in which the liquid phase of the liquefied gas is pushed out to the outside of the container body and the leakage of the liquefied gas cannot be stopped. On the other hand, when the liquid phase of the liquefied gas needs to be led out from the container main body through the lead-out flow path, the flow loss in the case where the liquid phase of the liquefied gas is led out to the outside of the container main body through the lead-out pipe can be reduced by closing the connection flow path with the open/close valve by the control device.

In the liquefied gas storage tank, the communication portion may be a communication hole provided in the discharge pipe so as to communicate a position where the gas phase of the liquefied gas is present with the discharge flow path in the container main body.

By providing the communication hole as the communication portion in this manner, the gas phase of the liquefied gas in the container main body can be caused to flow into the lead-out flow path with a very simple configuration, and the pressure in the lead-out flow path can be made equal to the pressure in the gas phase of the liquefied gas. Therefore, even if a failure occurs in the lead-out pipe outside the container body and the lead-out flow path is opened to the atmosphere, it is possible to avoid a situation in which the liquid phase of the liquefied gas is pushed out to the outside of the container body and the leakage of the liquefied gas cannot be stopped.

Further, the liquefied gas storage tank may further include: an atmosphere opening pipe provided in the container body and capable of communicating a position where the gas phase of the liquefied gas is present with an outside of the container body; and a valve capable of opening and closing a flow path inside the atmosphere opening pipe.

By providing such a valve, the pressure inside the container can be reduced before the pressure inside the container main body exceeds the design pressure.

A ship according to a first aspect of the present invention includes the liquefied gas storage tank described above.

According to such a ship, by providing the liquefied gas storage tank described above, the gaseous phase of the liquefied gas can be introduced into the lead-out flow path by the communication portion, and the pressure of the lead-out flow path can be equalized to the pressure of the gaseous phase of the liquefied gas. As a result, even if a trouble occurs in the lead-out pipe outside the container body and the lead-out flow path is opened to the atmosphere, it is possible to avoid a situation in which the liquid phase of the liquefied gas is pushed out to the outside of the container body and the leakage of the liquefied gas cannot be stopped.

Effects of the invention

According to the liquefied gas storage tank and the ship, leakage of liquefied gas can be suppressed with a simple structure.

Drawings

Fig. 1 is a side view of a ship according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view of a fuel tank of a ship according to a first embodiment of the present invention, and is an X-X sectional view in fig. 1.

Fig. 3 is a longitudinal sectional view of a fuel tank of a ship according to a second embodiment of the present invention.

Fig. 4 is a longitudinal sectional view of a fuel tank of a ship according to a third embodiment of the present invention.

Detailed Description

(first embodiment)

A ship 100 according to a first embodiment of the present invention will be described.

As shown in fig. 1, a ship 100 according to the present embodiment is a Liquefied Gas carrier that transports Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG) as Liquefied Gas.

As shown in fig. 1, a ship 100 includes: hull 10, bridge building 20, cargo tank 30, main engine 40, and fuel tank (liquefied gas storage tank) 50.

The hull 10 has: sides 11, bottom 12 and upper deck 13. The side 11 has a pair of left and right side outer plates 11 a. The bottom 12 has a bottom outer plate 12a that connects the left and right side outer plates 11a to each other at the lower portion.

The upper deck 13 is connected to a pair of side outer boards 11a at a position above the bottom 12. The upper deck 13 is a weather deck extending from the bow 10a to the stern 10 b. The upper deck 13 extends in a horizontal direction. The stern 10b side of the ship 100 is lowered according to the sailing state of the ship 100, and the stern 10b side of the upper deck 13 may be inclined downward.

The hull 10 has a substantially box-like cross section perpendicular to the fore-aft direction, and a space is formed therein, by the sides 11, the bottom 12, and the upper deck 13. The stern 10b side portion of the hull 10 serves as a nacelle 14. A part of the hull 10 on the bow 10a side of the nacelle 14 is a cargo hold 15 defined by the nacelle 14 and a bulkhead 15 a.

The bridge 20 is provided to extend upward from an upper portion of the hull 10. The bridge 20 is provided on the stern 10b side of the upper part of the hull 10 and above the nacelle 14. The bridge 20 is multi-layered. A control cabin 21 for controlling the ship 100 is provided at an upper level of the bridge 20. The cage 21 is configured to be able to look ahead of the ship 100 from a high position.

The cargo tanks 30 are arranged in plural numbers (three in the present embodiment) in the ship-to-ship direction in the cargo hold 15 of the hull 10. A bulkhead 15b that partitions a region for accommodating each cargo tank 30 is provided between adjacent cargo tanks 30.

The cargo tank 30 of the present embodiment is a square tank configured by joining flat plate-shaped tank wall portions to each other. In the cargo tank 30, liquefied gas (LNG or LPG) as cargo is stored in a normal pressure and low temperature state. The "normal pressure low temperature state" refers to a state in which the liquefied gas is maintained in a liquefied state by merely being brought to a low temperature without pressurizing the liquefied gas. The ship 100 is provided with an evaporation gas processing apparatus, not shown, for maintaining LPG in a liquefied state at a low temperature. As the boil-off gas processing apparatus, a reliquefaction apparatus is used. The reliquefaction device cools and reliquefies the boil-off gas discharged by the liquefied gas in the cargo tank 30 being vaporized by external heat outside the cargo tank 30. The gas thus liquefied is returned as liquefied gas to the cargo tank 30.

The main machine 40 is disposed in the nacelle 14 inside the hull 10. The main unit 40 of the present embodiment is driven using a liquefied gas LG such as LNG or LPG as a fuel. Here, the liquefied gas LG serving as the fuel of the main engine 40 is not limited to LNG or LPG, and may be other liquefied gas fuel or the like. The propeller 41 provided below the stern 10b of the hull 10 is rotated by the driving of the main unit 40.

Next, the fuel tank 50 will be described with reference to fig. 1 and 2. In the present embodiment, the fuel tank 50 is provided on the upper deck 13 via the tank support portion 51. The fuel tank 50 is provided on the upper deck 13 above the central cargo tank 30 among the three cargo tanks 30 arranged in the fore-aft direction, for example.

As shown in fig. 2, the fuel tank 50 includes: a container body 60 capable of storing the liquefied gas LG in a high-pressure state; a pump 62 and a lead-out pipe 63 for leading out the liquefied gas LG in the container body 60 to the outside of the container body 60; and a communication portion 65 that communicates the interior of the container body 60 with the interior of the lead-out pipe 63 outside the container body 60.

The container body 60 is formed of a pressure-resistant container. The design pressure (pressure resistance) of the container body 60 is higher than the head pressure of the liquefied gas LG at the liquid level height position h of the container body 60. Here, the liquid surface height position h represents a distance in the vertical direction from the upper end of the inner surface of the container body 60 to the liquid surface of the liquefied gas LG. The liquid head pressure of LNG per 1m is about 50(kPa), and therefore, in the case where the liquefied gas LG is LNG and the liquid level height position h of the container body 60 is 2(m), the design pressure of the container body 60 is greater than about 100 kPa. That is, the pressure in the container body 60 is a pressure sufficient to push the liquid phase L of the liquefied gas LG in the container body 60 to the upper portion of the container body 60, and as a result, the pressure in the container body 60 becomes higher than the atmospheric pressure and the liquid phase L of the liquefied gas LG can be pressed.

An atmosphere opening pipe 72 capable of communicating a position where the gas phase G of the liquefied gas LG is present with the outside of the container body 60 and a safety valve 71 capable of opening and closing a flow path inside the atmosphere opening pipe 72 are provided at an upper portion of the container body 60. The safety valve 71 is provided to release the gas phase inside the container to the atmosphere before the pressure inside the container main body 60 exceeds the design pressure.

The pump 62 is provided inside the container body 60, and pumps the liquefied gas LG inside the container body 60 to the main unit 40. A driving unit such as a motor for driving the pump 62 may be provided inside the container body 60 or may be provided outside the container body 60. In particular, since the liquefied gas LG stored in the container body 60 has insulation properties, there is no problem even if the driving portion is provided in the container body 60. The pump 62 is disposed in the bottom portion 60a of the container body 60 or in the vicinity of the bottom portion 60a so as to be disposed in the liquid phase L of the liquefied gas LG stored in the lower portion of the container body 60 inside the container body 60.

The lead-out pipe 63 extends in the vertical direction throughout the inside and outside of the container body 60. Thereby, the lead-out pipe 63 extends upward from the upper portion of the container body 60. One end of the lead-out pipe 63 is connected to a discharge port (not shown) of the pump 62 inside the container body 60. That is, one end of the lead-out pipe 63 opens into the liquid phase L of the liquefied gas LG. The other end of the lead-out pipe 63 is connected to the main unit 40. That is, the other end of the lead-out pipe 63 is disposed outside the container body 60. A lead-out passage 64 for guiding the liquid phase L of the liquefied gas LG in the container body 60 to the main unit 40 is formed inside the lead-out pipe 63. In the container body 60, a gas phase G generated by evaporation of the liquefied gas LG exists on the liquid surface of the liquid phase L of the liquefied gas LG.

In the present embodiment, the communicating portion 65 is a connecting pipe having therein a connecting flow path 66 capable of communicating the position where the gas phase G of the liquefied gas LG is present in the container body 60 with the lead-out flow path 64. The connection pipe is provided outside the container main body 60, and is branched from the lead-out pipe 63 between the container main body 60 and the main unit 40 to be connected to the upper portion of the container main body 60 where the gas phase G exists.

The connection pipe is provided with an on-off valve 67 capable of opening and closing the connection flow path 66. The on-off valve 67 is, for example, a remote control valve, and is a three-way valve provided at a position where a connection pipe branches from the lead-out pipe 63. The three-way valve is provided so as to be capable of switching between a first state S1 in which the lead-out flow path 64 is communicated between one end and the other end of the lead-out pipe 63 and the connection flow path 66 is closed, and a second state S2 in which the connection flow path 66 is opened by communicating one end of the lead-out pipe 63 with the connection flow path 66 via the lead-out flow path 64. For example, the three-way valve may be a manual valve.

Here, the fuel tank 50 further includes a control device 75 for operating the opening/closing valve 67. The controller 75 has a processor and the like, and switches between the first state S1 and the second state S2 of the on-off valve 67 based on the operation command. In the present embodiment, the normal on-off valve 67 is set to the second state S2 in which the connection flow path 66 is open, and when the liquefied gas LG is led out from the container body 60 through the lead-out flow path 64, the controller 75 sets the on-off valve 67 to the first state S1, and closes the connection flow path 66 by the on-off valve 67.

In the ship 100 of the present embodiment described above, it is assumed that a problem occurs in the lead-out pipe 63 outside the container body 60 of the fuel tank 50, and the lead-out flow path 64 is opened to the atmosphere in the middle thereof. The "failure state" indicates, for example, a failure of a gasket (not shown) of the opening/closing valve 67 as shown in a portion a in fig. 2, and is a state in which the lead-out flow path 64 is opened to the atmosphere at a middle portion of the lead-out pipe 63 outside the container main body 60.

When such a problem occurs, if the pressure in the container body 60 becomes higher than the atmospheric pressure due to evaporation of the liquefied gas LG, the liquid phase L of the liquefied gas LG in the container body 60 is pushed out to the outside of the container body 60 by the pressure difference between the atmospheric pressure and the pressure inside the container body 60, and leaks. In this embodiment, even in such a case, the gas phase G of the liquefied gas LG can be introduced into the lead-out flow passage 64 by the connection pipe serving as the communication portion 65, and therefore the pressure in the lead-out flow passage 64 can be made equal to the pressure of the gas phase G of the liquefied gas LG.

As a result, it is possible to avoid a situation in which the liquid phase L of the liquefied gas LG is arbitrarily pushed out to the outside of the container body 60 due to the pressure difference between the atmospheric pressure and the pressure inside the container body 60, and the leakage of the liquefied gas LG cannot be stopped. Therefore, it is possible to avoid a situation in which the liquid phase L continues to leak, and most or almost all of the liquefied gas LG in the container body 60 is discharged to the outside of the container body 60. Thus, leakage of the liquefied gas LG from the tank can be suppressed by a simple structure in which the connection pipe is provided in the container body 60. Also, a large drip tray for receiving a large amount of leaked liquefied gas LG is not required.

Even when the above-described problem occurs in the external lead-out pipe 63 of the vessel body 60 during the voyage of the ship 100 and the liquefied gas LG leaks from the lead-out flow path 64, if the opening/closing valve 67 is always set to the second state S2 and the connection flow path 66 is opened, the connection flow path 66 and the lead-out flow path 64 can be communicated with each other, and the pressure of the lead-out flow path 64 and the pressure of the gas phase G of the liquefied gas LG can be equalized. As a result, leakage of the liquefied gas LG can be suppressed. Further, when it is necessary to lead the liquefied gas LG out of the container body 60 through the lead-out flow path 64, that is, when supplying the liquefied gas LG to the main unit 40, the controller 75 can bring the on-off valve 67 into the first state S1 to close the connection flow path 66, and therefore, flow loss in a case where the liquefied gas LG is led out to the main unit 40 through the lead-out pipe 63 can be reduced.

Further, by providing the relief valve 71, the pressure inside the container body 60 can be reduced before the pressure inside the container body 60 exceeds the design pressure.

(second embodiment)

Next, a ship 100 according to a second embodiment of the present invention will be described with reference to fig. 3. In the second embodiment to be described below, the same portions as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the ship 100 of the present embodiment, the fuel tank 80 is different from that of the first embodiment.

The on-off valve 87 of the fuel tank 80 is a remote control valve provided in a connection pipe as the communication portion 85. The lead-out pipe 63 is provided with a lead-out valve 88 in addition to the opening/closing valve 67. The lead-out valve 88 may open the lead-out flow path 64 when the liquefied gas LG needs to be supplied to the main engine 40, or may open the lead-out flow path 64 at all times. The lead-out valve 88 is provided on the main unit 40 side of the position where the connection pipe branches from the lead-out pipe 63. The on-off valve 87 may be a manual valve.

The control device 75 operates the on-off valve 87. In the present embodiment, normally, when the connection passage 86 of the connection pipe is opened and the liquefied gas LG is led out from the container body 60 through the lead-out passage 64 and supplied to the main unit 40, the controller 75 operates the on-off valve 87 to close the connection passage 86 by the on-off valve 87.

In the ship 100 of the present embodiment described above, when a trouble occurs in the lead-out pipe 63 and the lead-out passage 64 is open to the atmosphere, the gas phase G of the liquefied gas LG can be introduced into the lead-out passage 64 through the connection pipe. Therefore, the pressure in the lead-out flow path 64 can be made equal to the pressure of the gas phase G of the liquefied gas LG. As a result, it is possible to prevent the liquid L from continuously leaking from the container body 60 and to prevent all of the liquefied gas LG in the container body 60 from being discharged to the outside of the container body 60. Thus, leakage of the liquefied gas LG can be suppressed with a simple structure in which the connection pipe is provided in the container body 60.

Even when a failure occurs in the external lead-out pipe 63 of the vessel body 60 during the voyage of the ship 100 and the liquefied gas LG leaks from the lead-out flow passage 64, the leakage of the liquefied gas LG can be suppressed by opening the connection flow passage 86 by the opening/closing valve 87 at all times. When it is necessary to lead the liquefied gas LG from the container body 60 through the lead-out passage 64 and supply the liquefied gas LG to the main unit 40, the controller 75 can close the connection passage 86 by actuating the on-off valve 87. This can reduce the flow loss when the liquefied gas LG is led out to the outside of the container body 60 through the lead-out pipe 63.

Further, leakage of the liquefied gas LG can be easily suppressed only by additionally providing the connection pipe and the opening/closing valve 87 as the communication portion 85 to a fuel tank that does not include the connection pipe and the opening/closing valve 87.

(third embodiment)

Next, a ship 100 according to a third embodiment of the present invention will be described with reference to fig. 4. In the third embodiment to be described below, the same portions as those in the first and second embodiments are denoted by the same reference numerals, and redundant description is omitted. In the ship 100 of the present embodiment, the fuel tank 90 is different from the first and second embodiments.

The fuel tank 90 does not include the connection pipe and the opening/closing valves 67 and 87. That is, in the present embodiment, the communication portion 95 is a communication hole provided in the discharge pipe 63 in the container main body 60 so as to communicate the discharge flow path 64 with a position where the gas phase G of the liquefied gas LG is present in the container main body 60.

For example, when the inner diameter of the lead-out pipe 63 is 40(mm), the diameter of the communication hole is preferably 10(mm) to 20 (mm).

In the ship 100 of the present embodiment described above, by providing the communication hole as the communication portion 95, the gas phase G of the liquefied gas LG can be caused to flow into the lead-out flow passage 64 with a very simple configuration, and the pressure in the lead-out flow passage 64 can be made equal to the pressure of the gas phase G of the liquefied gas LG. As a result, even if a trouble occurs in the outlet pipe 63 outside the container body 60 and the outlet flow path 64 is opened to the atmosphere, it is possible to suppress the liquid phase L of the liquefied gas LG from being pushed out to the outside of the container body 60 due to the pressure difference between the atmospheric pressure and the pressure inside the container body 60. Therefore, it is possible to avoid a situation where the leakage of the liquefied gas LG from the container body 60 cannot be stopped by a very simple structure.

While the embodiments of the present invention have been described above with reference to the drawings, the configurations of the embodiments and combinations thereof are merely examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The present invention is not limited by the embodiments, but is defined only by the claims.

For example, when a trouble occurs in the lead-out pipe 63, a sensor detects a leak, and the controller 75 may operate the opening/closing valves 67 and 87 based on the detection result of the sensor to open the connection passages 66 and 86. The control device 75 may control the relief valve 71.

The lead-out pipe 63 is not limited to a pipe for supplying the liquefied gas LG to the main unit 40. For example, the sampling pipe may be provided separately from a pipe for supplying the liquefied gas LG to the main unit 40. The sampling tube is a pipe for taking out the liquefied gas LG in the container body 60 for sampling.

The safety valve 71 may be an on-off valve provided in a pipe connected to a portion of the gas phase G in the container main body 60.

The liquefied gas storage tank is not limited to the fuel tank 50 mounted on the ship 100, and may be, for example, a liquefied gas storage tank installed on the ground.

Description of the reference numerals

10 … boat hull

10a … bow

10b … stern

11 … broadside

11a … side shell plate

12 … ship bottom

12a … bottom planking

13 … Upper Board

14 … cabin

15 … cargo tank

15a … bulkhead

15b … bulkhead

20 … bridge

21 … control cabin

30 … cargo oil tank

40 … host computer

41 … screw propeller

50. 80, 90 … fuel tank (liquefied gas storage tank)

51 … Can support

60 … Container body

60a … bottom

62 … pump

63 … lead-out pipe

64 … lead-out flow path

65. 85, 95 … communicating part

66. 86 … connecting flow path

67. 87 … opening and closing valve

75 … control device

71 … safety valve

72 … atmosphere opening pipe

88 … discharge valve

100 … Ship

LG … liquefied gas

L … liquid phase

G … gas phase

S1 … first State

S2 … second state.