Ship, method and fuel tank

Abstract

The present disclosure relates to a fuel tank (1) for a ship (10). The fuel tank (1) comprises a gas-tight manhole (2) provided on an upper portion of the fuel tank (1) and configured to access from above the fuel tank (1) in a use position of the fuel tank to provide access to the fuel tank (1). The fuel tank (1) is a single-shell fuel tank and comprises a tank connection space (4) provided at an end (5) or on a side (6) of the fuel tank, the tank connection space (4) comprising a gas-tight compartment containing a tank penetration (42) and a tank valve (43) for the fuel. The fuel tank (1) is provided with a sub-closure (7) that covers the access hole (2) and delimits a first space (8) between the access hole (2) and the sub-closure (7), the first space (8) forming an airtight compartment that isolates the first space (8) from the tank holding space (9). An access to the tank connection space (9) is provided through the second space (19). Ventilation is provided in the secondary closure (7), the tank connection space (9) and the second space (19).

Description

Technical Field

[0001] The present disclosure relates to marine vessels, and more particularly to fuel tanks and methods related to marine vessels. Background Art

[0002] Fuels used in ships (e.g., hydrocarbon gases or ammonia) can be hazardous and / or explosive themselves, or can form hazardous and / or explosive mixtures or compounds, for example with air. This must be taken into account when designing structures designed to hold such fuels, such as fuel tanks. In particular, all penetrations made in the tank's hull, such as pipes, instruments, and manholes, are considered potential risk areas for leakage. Summary of the Invention

[0003] An object of the present disclosure is to provide a new fuel tank, vessel and method.

[0004] The objects of the present disclosure are achieved by a method and an apparatus which are characterized by what is stated in the independent claims. Some embodiments of the present disclosure are disclosed in the dependent claims.

[0005] The present disclosure is based on a technical structure in which an airtight and ventilated secondary enclosure is provided to surround an airtight manhole of a fuel tank of a ship, the secondary enclosure being separated from a tank connection space of the fuel tank.

[0006] An advantage of the method and apparatus disclosed herein is that a fuel tank having more compact dimensions and, in particular, a lower structure can be provided compared to a fuel tank in which the manhole is provided in the tank connection space. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Hereinafter, the present disclosure will be described in more detail by way of preferred embodiments with reference to the accompanying drawings, in which:

[0008] Figure 1 Schematically illustrates a fuel tank according to one embodiment, seen from the side;

[0009] Figure 2 shows schematically a partial cross-sectional view of a detail of a fuel tank according to one embodiment, seen from the direction of the end of the fuel tank;

[0010] Figure 3 shows schematically a partial cross-sectional view of a detail of a fuel tank according to one embodiment, seen from the direction of the end of the fuel tank;

[0011] Figure 4 Schematically shows the shape of a fuel tank according to one embodiment as viewed from the side;

[0012] Figure 5Schematically shows the shape of a fuel tank according to one embodiment as seen from the end;

[0013] Figure 6 Schematically illustrates a vessel according to an embodiment;

[0014] Figure 7 Schematically shows a cross-sectional view of a vessel according to an embodiment as seen from the side;

[0015] Figure 8 schematically shows a cross-sectional view of a vessel according to another embodiment, seen from the end; and

[0016] Figure 9 The method is schematically illustrated in relation to a vessel. DETAILED DESCRIPTION

[0017] The present disclosure relates to a fuel tank for a vessel, a vessel, and a method related to a vessel.

[0018] Figure 1 A fuel tank according to one embodiment is schematically shown as seen from the side, and Figure 2 A cross-sectional view of a detail of a fuel tank according to one embodiment is schematically shown, seen from the direction of the end of the fuel tank.

[0019] The fuel tank 1 for a vessel 10 comprises a gas-tight manhole 2 provided on an upper portion 3 of the fuel tank 1. The vessel 10 comprises a hull 11 and a deck 12. The fuel tank 1 may comprise, for example, a hydrocarbon gas or ammonia fuel tank. Figure 1 In the embodiment of FIG. 1 , the manhole 2 is configured to be accessible from above the fuel tank 1 when the fuel tank 1 is in use to provide access to the fuel tank 1. In other words, the manhole 2 is configured to enable an end user (e.g., maintenance personnel) to access the manhole 2 from above the fuel tank, thereby accessing the interior of the fuel tank 1. However, the manhole 2 is typically rarely used to access the fuel tank 1, typically only during maintenance outages.

[0020] The use position of the fuel tank 1 refers to the position of the fuel tank 1 when the fuel tank 1 is installed on the vessel 10. More specifically, the use position of the fuel tank 1 refers to the position of the fuel tank 1 when the fuel tank 1 is installed on the vessel 10 and when the vessel 10 is in a neutral position. Similarly, the use position of the vessel 10 refers to the position of the vessel 10 when the vessel 10 is in a neutral position. In other words, the use position of the fuel tank 1 or the vessel 10 does not refer to the extreme positions of the fuel tank 1 or the vessel 10 under changing weather conditions, for example.

[0021] The disclosed fuel tank 1 is a single-shell fuel tank. The fuel tank 1 includes a tank connection space 4 arranged at the end 5 or on the side 6 of the fuel tank, the tank connection space 4 including an airtight compartment that accommodates a tank penetration piece 42 and a tank valve 43 for fuel. In other words, the tank penetration piece 42 and the tank valve 43 for fuel, preferably all tank penetration pieces 42 and tank valves 43 for fuel, are arranged in the tank connection space 4. According to one embodiment, the fuel tank 1 includes a tank connection space 4 arranged at the end 5 of the fuel tank 1. The tank connection space 4 being arranged at the end 5 of the fuel tank 1 means that the tank connection space 4 covers at least a portion of the end 5 of the fuel tank 1. In other words, the tank connection space 4 can be partially limited by the end 5 of the fuel tank 1, for example on one side of the tank connection space 4. According to one embodiment, the tank connection space 4 provided at the end 5 of the fuel tank 1 may cover the entire end 5 of the fuel tank 1 and only cover the end 5 of the fuel tank 1. In other words, it may not extend to the side 6 above or below the fuel tank 1, more specifically, it may not extend to one or both of the side 6 above or below the shell 32 of the fuel tank 1. According to one embodiment, the tank connection space 4 provided at the end 5 of the fuel tank 1 may cover the entire end 5 of the fuel tank 1 and further extend to at least one of the following areas: one side 6 of the fuel tank 1; both sides 6 of the fuel tank 1; above the shell 32 of the fuel tank 1; and below the shell 32 of the fuel tank 1. According to one embodiment, the tank connection space 4 provided at the end 5 of the fuel tank 1 may cover the entire end 5 of the fuel tank 1 and further extend to at least one side 6 of the fuel tank 1 and further extend above and / or below the shell 32 of the fuel tank 1. According to one embodiment, the tank connection space 4 provided at the end 5 of the fuel tank 1 may only cover a portion of the end 5 of the fuel tank 1 and only cover that portion of the end 5 of the fuel tank 1. According to one embodiment, the tank connection space 4 disposed at the end 5 of the fuel tank 1 may cover a portion of the end 5 of the fuel tank 1 and further extend to at least one of the following areas: one side 6 of the fuel tank 1; both sides 6 of the fuel tank 1; above the housing 32 of the fuel tank 1; and below the housing 32 of the fuel tank 1. The tank connection space 4 disposed on the side 6 of the fuel tank 1 means that the tank connection space 4 covers at least a portion of the side 6 of the fuel tank 1. In other words, the tank connection space 4 disposed on the side 6 of the fuel tank 1, in addition to covering a portion of the side 6, may also extend above the housing 32 of the fuel tank 1 and / or below the housing 32 of the fuel tank 1. Such an embodiment may be advantageous because a compact fuel tank 1 may be provided, and in particular, the height and width of the fuel tank may be kept to a minimum.

[0022] Furthermore, the fuel tank 1 is provided with a secondary closure 7, which covers the manhole 2 and restricts a first space 8 between the manhole 2 and the secondary closure 7, for providing access to the manhole 2. In other words, the secondary closure 7 is configured to cover the manhole 2. Thus, the secondary closure 7 is also configured to restrict a first space 8 provided between the manhole 2 and the secondary closure 7. The first space 8 extends at least around and above the manhole 2, and when closed, forms an airtight compartment that isolates the first space 8 from the tank holding space 9. Therefore, the manhole 2 and the secondary closure 7 provide double protection for access to the interior of the fuel tank 1, as the interior of the fuel tank 1 is configured to be accessed first through the secondary closure 7 and then through the manhole 2, both of which provide an airtight structure when closed and define a space, namely the first space 8, therebetween.

[0023] The tank holding space 9 includes a space surrounding the fuel tank 1, the tank connecting space 4, and the secondary enclosure 7. According to one embodiment, the fuel tank 1 is provided below the deck 12, and the tank holding space 9 includes a space surrounding the fuel tank 1, the tank connecting space 4, and the secondary enclosure 7.

[0024] According to one embodiment, both the manhole 2 and the secondary closure 7 comprise airtight covers 27, 28, respectively. Figure 3 Best seen in Figure 3 A partial cross-sectional view schematically illustrates a detail of a fuel tank according to an embodiment, viewed from the end of the fuel tank. The fact that the manhole cover 27 and the secondary closure cover 28 are airtight means that the manhole cover 27 and the secondary closure cover are constructed to be airtight. Providing airtight ventilation to the secondary closure 7 and the first space 8 ensures safety even in the event of a leak in the airtight structure.

[0025] According to one embodiment, the airtight cover 27 of the manhole and the airtight cover 28 of the secondary closure can be arranged one after another in a spaced manner in the direction of travel. The direction of travel refers to the direction in which the manhole 2 is configured to be accessed via the secondary closure 7. According to an embodiment, the cover 27 of the manhole and the cover 28 of the secondary closure are arranged one above the other in the vertical direction 26.

[0026] According to one embodiment, at least the cover 28 of the secondary enclosure comprises a maintenance hatch, which is mounted to the rest of the secondary enclosure 7 in a locking manner by bolts 29. According to one embodiment, at least one of the bolts 29 is locked in the closed position by welding. In other words, the maintenance hatch can be mounted to the rest of the secondary enclosure 7 in a locking manner by welding at least one bolt 29 to lock it in the closed position. According to one embodiment, in addition to or instead of at least one bolt 29 that is locked in the closed position, the cover 28 of the secondary enclosure comprises a separate locking device (not shown) for locking the cover to the closed position. In other words, the maintenance hatch can be mounted to the rest of the secondary enclosure 7 in a locking manner by a separate locking device. Such a locking device may comprise, for example, a lock, such as a padlock-type lock, which has a specific key that is accessible only to authorized personnel.

[0027] According to an embodiment, the cover 28 of the secondary enclosure is mounted by means of a mounting flange 30 and bolts 29 mounted through the mounting flange 30 .

[0028] According to an embodiment, the manhole cover 27 comprises a maintenance hatch similar to the embodiment or combination of embodiments disclosed in connection with the secondary closure cover 28. According to another embodiment, the manhole cover 27 comprises a hatch welded to the rest of the manhole 2 structure instead of or in addition to being mounted by bolts.

[0029] According to one embodiment, the cover 27 of the manhole and / or the cover 28 of the secondary closure are designed to be removable or detachable in one piece, but the removal or detachment is configured to require special equipment, in other words, equipment that is different from, for example, equipment designed for removing bolts, etc. In other words, the manhole 2 and the secondary closure 7 can be configured to be accessible, but access requires special tools or equipment, or the ease of access is limited in some other way. According to one embodiment, the cover 27 of the manhole and / or the cover 28 of the secondary closure are designed to be reinstallable after being removed or detached. According to an embodiment, the weld lock of the cover 27 of the manhole and / or the cover 28 of the secondary closure can be configured to form a seal that provides a visible indication of whether the cover 27, 28 in question has been opened.

[0030] The secondary enclosure 7 is provided with a first ventilation inlet 13 and a first ventilation outlet 15. The first ventilation inlet 13 is configured to connect the first space 8 to the inlet ventilation duct 14, and the first ventilation outlet 15 is configured to connect the first space 8 to the outlet ventilation duct 16. Therefore, both the secondary enclosure 7 and the manhole 2 are formed into an airtight structure, and the first space 8 provided between the manhole 2 and the secondary enclosure 7 is ventilated via the first ventilation inlet 13 and the first ventilation outlet 15.

[0031] The tank connection space 4 is provided with a second ventilation inlet 17 configured to connect the tank connection space 4 to the inlet ventilation duct 14 and a second ventilation outlet 18 configured to connect the tank connection space 4 to the outlet ventilation duct 16 .

[0032] An inlet to the box connection space 4 is provided through the second space 19. The second space 19 comprises an airtight compartment and is provided with a third ventilation inlet 20 configured to connect the second space 19 to the inlet ventilation duct 14 and a third ventilation outlet 21 configured to connect the second space 19 to the outlet ventilation duct 16.

[0033] According to one embodiment, ventilation is provided for the secondary enclosure 7, the tank connection space 4, and the second space 19. Preferably, the ventilation of the secondary enclosure 7, the tank connection space 4, and the second space 19 is configured to be arranged and / or controlled separately in such a manner that the ventilation in each space 8, 4, 19 can be determined and controlled separately according to different needs and requirements. This can be provided by providing separate inlet ventilation ducts 14 and / or separate outlet ventilation ducts 16 for the secondary enclosure 7, the tank connection space 4, and the second space 19. Therefore, although the inlet ventilation duct 14 and the outlet ventilation duct 16 use the same reference numerals, the inlet ventilation duct 14 and / or the outlet ventilation duct 16 for each of the secondary enclosure 7, the tank connection space 4, and the second space 19 can include separate ducts that are not connected to each other.

[0034] According to one embodiment, the outlet ventilation duct 16 is isolated from the tank holding space 9. In other words, the contents of the outlet ventilation duct 16 are isolated from the tank holding space 9, which surrounds the fuel tank 1, the tank connection space 4, and the secondary enclosure 7. According to one embodiment, the outlet ventilation duct 16 is configured to guide the outlet air from the first space 8, the tank connection space 4, and the second space 19, respectively, to the outside air outside the tank holding space 9. According to this embodiment, the outlet ventilation duct 16 may include separate ducts or lines for the outlet air from the first space 8, the tank connection space 4, and the second space 19, which are not connected to each other in any way, or two or more of the ducts or lines connected to the first space 8, the tank connection space 4, and / or the second space 19 may be connected to each other at a point within the tank holding space 9 or outside the hull 11 of the vessel 10.

[0035] According to one embodiment, the first space 8 and the box connection space 4 at least partially share the outlet ventilation duct 16. In other words, at least a portion of the outlet ventilation duct 16 connected to the first ventilation outlet 15 and the outlet ventilation duct 16 connected to the second ventilation outlet 18 can be connected to a single pipe or pipeline. According to one embodiment, a branch 23 connecting the outlet ventilation duct 16 connected to the first ventilation outlet 15 and the outlet ventilation duct 16 connected to the second ventilation outlet 18 is provided downstream of the first ventilation outlet 15 and the second ventilation outlet 18. In other words, the branch 23 connecting the outlet ventilation duct 16 connected to the first ventilation outlet 15 and the outlet ventilation duct 16 connected to the second ventilation outlet 18 can be provided downstream of the first space 8 and the box connection space 4. Thus, the branch 23 can be provided outside the first space 8 and the box connection space 4.

[0036] According to one embodiment, the inlet ventilation duct 14 is isolated from the tank holding space 9. In other words, the contents of the inlet ventilation duct 14 are isolated from the tank holding space 9. According to one embodiment, the inlet ventilation duct 14 is configured to guide the inlet air to the first space 8, the tank connection space 4, and the second space 19, respectively. According to this embodiment, the inlet ventilation duct 14 may include separate pipes or lines for allowing air to enter the first space 8, the tank connection space 4, and the second space 19, and these separate pipes are not connected to each other in any way, or two or more of the pipes or lines connected to the first space 8, the tank connection space 4, and / or the second space 19 may be connected to each other at a point inside the tank holding space 9 or outside the hull 11 of the vessel 10.

[0037] According to one embodiment, the first space 8 and the box connection space 4 at least partially share an inlet ventilation duct 14. In other words, at least a portion of the inlet ventilation duct 14 connected to the first ventilation inlet 13 and the inlet ventilation duct 14 connected to the second ventilation inlet 17 can be connected to a single pipe or pipeline. According to one embodiment, a branch 23 connecting the inlet ventilation duct 14 connected to the first ventilation inlet 13 and the inlet ventilation duct 14 connected to the second ventilation inlet 17 is provided upstream of the first ventilation inlet 13 and the second ventilation inlet 17. In other words, the branch 23 connecting the inlet ventilation duct 14 connected to the first ventilation inlet 13 and the inlet ventilation duct 14 connected to the second ventilation inlet 17 can be provided upstream of the first space 8 and the box connection space 4. Thus, the branch 23 can be provided outside the first space 8 and the box connection space 4.

[0038] According to one embodiment, the first space 8 is configured to be ventilated at least 10 times per hour, i.e., ventilated via the first ventilation inlet 13 and the first ventilation outlet 15. In other words, an amount of air equal to at least 10 times the volume of the first space 8 can be supplied to the first space 8 via the first ventilation inlet 13 and exit the first space 8 via the first ventilation outlet 15 within one hour. According to one embodiment, the first space 8 is configured to be ventilated at least 30 times per hour via the first ventilation inlet 13 and the first ventilation outlet 15. According to one embodiment, the first space 8 is configured to be ventilated continuously at at least 10 times per hour (preferably at least 30 times per hour) during normal operation of the fuel tank 1, or the first space is ventilated continuously at at least 10 times per hour (preferably at least 30 times per hour) during normal operation of the fuel tank 1.

[0039] According to one embodiment, ventilation includes suction-based ventilation. More specifically, ventilation of the first space 8, the box connection space 4, and / or the second space 19 can be configured to be provided in a suction-based manner. In other words, ventilation can be provided by suction (in other words, negative pressure) provided at the first ventilation outlet 15, the second ventilation outlet 18, and / or the third ventilation outlet 21, rather than providing pressurized air to the first ventilation inlet 13, the second ventilation inlet 17, and / or the third ventilation inlet 20, respectively.

[0040] According to one embodiment, the first ventilation outlet 15 and / or the outlet ventilation duct 16 connected to the first ventilation outlet 15 is provided with a gas detector 22 configured to detect leakage from the fuel tank 1 to the first space 8. In other words, the gas detector 22 may be provided in fluid connection with the first ventilation outlet 15. This may be beneficial because leakage from the fuel tank to the first space 8 may be detected early, and safety may be ensured before maintenance personnel enter the first space 8 to access the manhole 2 and / or the fuel tank 1.

[0041] According to one embodiment, the secondary enclosure 7 is provided with a drain pipe 24 including a self-closing valve 25 for draining condensed water from the first space 8 using the self-closing valve 25. According to one embodiment, the self-closing valve 25 may include a low-temperature self-closing valve.

[0042] According to one embodiment, the manhole 2 is configured to be accessible from above the fuel tank 1 in the use position of the fuel tank 1 in the vertical direction 26. In other words, the manhole 2 can be configured to be accessible from directly above the manhole 2 or from substantially directly above the manhole 2.

[0043] According to another embodiment, the manhole 2 can be configured to be accessible from above the fuel tank 1 in the in-use position of the fuel tank 1 at an angle relative to the vertical direction 26. In other words, the manhole 2 is configured to be accessible at an angle (not shown) relative to the vertical direction. According to such an embodiment, the manhole 2 can be configured to be accessible at an angle of up to 45 degrees relative to the vertical direction 26. Approaching the manhole 2 from directly above the manhole 2 in the vertical direction 26 or in an angle within a range of 0 to 45 degrees relative to the vertical direction 26 can be beneficial to the safety of maintenance personnel accessing the manhole, for example.

[0044] According to one embodiment, the secondary closure 7 comprises a double plate 31 configured to be mounted against a shell 32 of the fuel tank 1 and configured to at least partially conform to the shape of a surface 33 of the shell 32 of the fuel tank 1 . Figure 3 An example of such an embodiment is schematically shown in .

[0045] According to one embodiment, the fuel tank 1 is configured to hold liquefied gas. According to one embodiment, the fuel tank 1 may be configured to hold hydrocarbon gas or ammonia.

[0046] According to one embodiment, the fuel tank is configured to meet the requirements of the relevant ATEX Directive, such as 2014 / 34 / EU, such as the requirements for the relevant equipment categories.

[0047] Figure 4 The figure schematically shows the shape of a fuel tank according to one embodiment as viewed from the side. Figure 5 The shape of a fuel tank according to one embodiment as viewed from the end is schematically shown. Figure 4 and Figure 5 However, fuel tanks 1 such as those disclosed in the present disclosure may also and typically may include a nearly circular or elliptical cross-section instead of Figure 5 Therefore, the rounded rectangle shown in Figure 4 and Figure 5 The shape of the fuel tank 1 is shown to illustrate only some features thereof, and the actual shape of the fuel tank 1 may also be different from the Figure 4 and Figure 5 shape, such as Figure 1 、 Figure 2 and Figure 3 The shape of the.

[0048] According to one embodiment, the fuel tank 1 has an elongated form. According to one embodiment, the maximum height 34 of the fuel tank 1 is less than or equal to 1.5 times the maximum width 35 of the fuel tank. According to one embodiment, the maximum height 34 of the fuel tank 1 is within a range of 0.5 to 1.5 times the maximum width 35 of the fuel tank. According to another embodiment, the maximum height 34 of the fuel tank 1 is less than or equal to the maximum width 35 of the fuel tank 1. Such fuel tanks 1 may be advantageous because they can be formed with a relatively low height and narrow width relative to the total internal volume of the fuel tank 1. Providing a relatively low manhole 2 and secondary closure 7 in the upper portion 3 of the fuel tank 1 and providing a separate tank connection space 4 at the end 5 of the fuel tank 1 (which necessarily requires a larger internal space) further contribute to achieving this elongated shape of the fuel tank 1. For example, a benefit of such an elongated fuel tank 1 is that it is easier to position within a vessel 10, as vessels 10 also typically have an elongated shape.

[0049] According to one embodiment, the fuel tank 1 at least partially has the form of a body of revolution. In other words, at least a portion of the fuel tank 1 may comprise the form of a body of revolution. According to one embodiment, the interior of the housing 32 of the fuel tank 1, i.e., the volume of the fuel tank 1 configured to receive fuel, may have the shape of a capsule, in other words, a spherical cylinder or a peanut-like shape that is narrower in the middle. According to one embodiment, the longitudinal direction 38 of the fuel tank extends in the direction of the axis of the body of revolution.

[0050] According to one embodiment, the maximum length 36 of the fuel tank 1 is in the range of 2 to 8 times the maximum diameter 37 of the fuel tank, measured in a direction transverse to the longitudinal direction 38 of the fuel tank 1 .

[0051] In the present disclosure, the height 34 of the fuel tank 1 refers to the maximum dimension of the fuel tank 1 in the vertical direction 26 when the fuel tank 1 is in the use position. Similarly, the width 35 of the fuel tank 1 refers to the maximum dimension of the fuel tank 1 in the horizontal direction perpendicular to the longitudinal direction 38 of the fuel tank 1 when the fuel tank 1 is in the use position. The maximum diameter 37 may include the height 34 and / or the width 35 of the fuel tank 1, or a diameter measured in another direction perpendicular to the longitudinal direction 38 of the fuel tank 1, depending on the shape of the fuel tank and its cross-section.

[0052] According to one embodiment, the fuel tank 1 is configured to be disposed on support structures 39 for supporting the fuel tank 1. These support structures 39 may include structures that are provided as an integral part of the fuel tank 1 or the vessel 10, or that are provided as separate structural parts that are configured to be mounted to the vessel 10.

[0053] According to one embodiment, in the use position of the fuel tank 1, the longitudinal direction 38 of the fuel tank 1 is arranged in a substantially horizontal direction. According to one embodiment, in the use position of the vessel 10, the longitudinal direction 38 of the fuel tank 1 is arranged in a substantially horizontal direction.

[0054] According to one embodiment, the volume of the fuel tank 1 is between 100 and 3000 m 3 According to another embodiment, the volume of the fuel tank 1 is between 300 and 2000m 3 According to another embodiment, the volume of the fuel tank is at least 300m 3 In other words, the fuel tank 1 disclosed in the present disclosure is a large fuel tank used in a large ship 10 .

[0055] According to one embodiment, the secondary closure 7 is disposed on the upper portion of the fuel tank 1. According to one embodiment, the secondary closure 7 can be disposed on the top surface of the fuel tank. In other words, the secondary closure 7 can be disposed at the level of the top centerline 40 of the fuel tank 1. According to another embodiment, the secondary closure 7 can be disposed on the upper portion of the fuel tank 1, which extends 30 degrees to either side of the top centerline 40 of the fuel tank 1, the top centerline 40 being parallel to the longitudinal direction 38 of the fuel tank 1. In other words, the secondary closure 7 is disposed on the top surface of the fuel tank 1 and / or within a surface area of the fuel tank 1 that extends up to 30 degrees to one or both sides of the top centerline 40 of the fuel tank 1.

[0056] According to one embodiment, at least a portion of the fuel tank's instrumentation (not shown) is disposed within the first space 8. According to one embodiment, at least a portion of the fuel tank's instrumentation is disposed within the tank connection space 4. In other words, at least a portion of the fuel tank's instrumentation may be disposed within the first space 8 and / or within the tank connection space 4. According to one embodiment, no fuel tank instrumentation is disposed within the first space 8. According to one embodiment, the fuel tank's instrumentation may include at least one of a liquid level gauge and a gas temperature measuring device. According to one embodiment, the fuel tank's instrumentation may also include other instruments.

[0057] According to one embodiment, the fuel tank 1 is configured to hold liquefied gas. According to one embodiment, the fuel tank 1 is configured to hold hydrocarbon gas or ammonia.

[0058] According to one embodiment, the access to the second space 19 and the tank connection space 4 can be bolted. According to one embodiment, the second space 19 can comprise a substantially airlocked space. According to one embodiment, the access to the second space can be configured to be closed by a lock suitable for a substantially airlocked space. Such an embodiment may be beneficial because access to the tank connection space 4 may be required more frequently than to the first space 8, and may also be required during operation of the fuel tank 1.

[0059] According to one embodiment, the tank connection space 4 is configured to be accessible through the second space 19. According to one embodiment, the entrance to the second space 19 and / or to the tank connection space 4 may be provided with a cover (not shown), such as a hatch or door. According to one embodiment, both the second space 19 and the tank connection space 4 include an airtight cover, and wherein the airtight cover of the second space and the airtight cover of the tank connection space are arranged one after another in a spaced-apart manner in the direction of travel.

[0060] According to one embodiment, the cover of the second space and the cover of the tank connection space are arranged vertically one above the other. According to one embodiment, the cover of the second space and / or the cover of the tank connection space may include a maintenance hatch that is bolted to the rest of the structure in a locking manner. According to one embodiment, at least one of the bolts is locked in the closed position by welding. According to one embodiment, the cover of the second space and / or the cover of the tank connection space may also include a separate locking device for locking the cover in the closed position.

[0061] According to one embodiment, the cover of the second space and / or the cover of the tank connection space may be mounted by means of a mounting flange and bolts mounted through the mounting flange.

[0062] According to one embodiment, the cover of the second space and / or the cover of the box connection space is designed to be removable or disassembled in one piece. According to one embodiment, the removal or disassembly can be configured to require special equipment, in other words, require equipment that is different from, for example, equipment designed for removing bolts, etc. In other words, the second space 19 and the box connection space 4 can be configured to be accessible, but access requires specific tools or equipment, or the ease of access is limited in some other way. According to one embodiment, the cover of the second space and / or the cover of the box connection space can be designed to be reinstallable after being removed or disassembled. According to one embodiment, the weld lock of the cover of the second space and / or the cover of the box connection space can be configured to form a seal that provides a visible indication of whether the cover in question has been opened.

[0063] According to one embodiment, the tank connection space is configured to be accessible from an end 5 or a side 6 of the fuel tank 1 .

[0064] According to one embodiment, the tank connection space 4 may be configured to be accessible from above the fuel tank 1. This may be beneficial in view of the safety of maintenance and operating personnel who need to access the tank connection space 4.

[0065] According to one embodiment, the fuel tank 1 may comprise a low temperature design.

[0066] Figure 6 Schematically illustrating a vessel according to an embodiment, Figure 7 A cross-sectional view of a vessel according to an embodiment is schematically shown as seen from the side, and Figure 8 A cross-sectional view of a vessel according to another embodiment is schematically shown, seen from the end.

[0067] The vessel 10 may include a hull 11, a deck 12, and a fuel tank 1 according to the embodiments disclosed in the present specification, the drawings, and the claims, or a combination of these embodiments. It is clear to a person skilled in the art that the vessel 10 includes a large number of other structural and functional components that are not relevant to the present disclosure and are therefore not disclosed in more detail herein.

[0068] According to one embodiment, the fuel tank 1 can be arranged within the hull 11 and below the deck 12 of the vessel 10. According to one embodiment, the vessel 10 can include a second fuel tank 41 below the deck 12. According to one embodiment, the fuel tanks 1 and 41 can be arranged side by side. According to another embodiment, the fuel tanks 1 and 41 can at least partially share a common ventilation device. According to one embodiment, the fuel tanks 1 and 41 at least partially share an inlet ventilation duct 14 and / or an outlet ventilation duct 16. According to another embodiment, the inlet ventilation duct 14 of the first fuel tank 1 is completely separate from the inlet ventilation duct of the second fuel tank 41. Similarly, according to one embodiment, the outlet ventilation duct 16 of the first fuel tank 1 is completely separate from the outlet ventilation duct of the second fuel tank 41. In other words, depending on the embodiment, the inlet ventilation duct 14 and / or outlet ventilation duct 16 for the first fuel tank 1 and the second fuel tank 41 can be completely separate, shared, or partially shared.

[0069] According to one embodiment, the at least one fuel tank 1 , 41 is configured to be arranged on a support structure 39 provided in the tank holding space 9 of the vessel 10 for supporting the fuel tank 1 .

[0070] According to one embodiment, the entire tank holding space 9 is provided below the deck. In other words, the tank holding space 9 may be defined around the fuel tanks 1 , 41 , the tank holding space 9 , the secondary enclosure 7 and the secondary space 19 within the hull 11 and below the deck 12 .

[0071] According to one embodiment, vessel 10 comprises a vessel classified according to an IGF or IGC code.

[0072] Figure 9 The method is schematically illustrated in relation to a vessel.

[0073] A method relating to a vessel 10 comprising a hull 11, a deck 12, and a fuel tank according to one or more of the embodiments disclosed in the present specification, drawings, and claims, or any combination thereof, may include isolating 91 a tank connection space 4 to form an airtight compartment housing a tank penetration 42 and a tank valve 43 for the fuel. The method may also include providing 93 a secondary closure 7 covering a manhole 2 and defining a first space 8 between the manhole 2 and the secondary closure 2, the first space 8 extending at least around and above the manhole. The method may also include configuring the secondary closure 95 to, when closed, form an airtight compartment isolating the first space 8 from a tank holding space 9 surrounding the fuel tank 1, the tank connection space 4, and the secondary closure 7. According to one embodiment, the tank holding space 9 may surround the fuel tank 1, the tank connection space 4, and the secondary closure 7 below the deck 12.

[0074] According to one embodiment, the method may further include ventilating the first space 8 via the first ventilation inlet 13 and the first ventilation outlet 15 at a rate of at least 30 air changes per hour.

Claims

1. A fuel tank for a ship, the ship comprising a hull and a deck, wherein: The fuel tank includes an airtight access hole provided on an upper portion of the fuel tank and configured to be accessible from above the fuel tank in a use position of the fuel tank to provide access to the fuel tank, It is characterized by: The fuel tank is a single-shell fuel tank; The fuel tank includes a tank connection space provided at an end or on a side of the fuel tank, the tank connection space including an airtight compartment accommodating a tank penetration and a tank valve for fuel; and the fuel tank being provided with a secondary closure, the secondary closure covering the manhole and defining a first space between the manhole and the secondary closure for providing access to the manhole, the first space extending at least around and above the manhole and forming an airtight compartment separating the first space from a tank holding space when closed, the tank holding space surrounding the fuel tank, the tank connecting space and the secondary closure; wherein the secondary enclosure is provided with a first ventilation inlet and a first ventilation outlet, the first ventilation inlet being configured to connect the first space to an inlet ventilation duct, and the first ventilation outlet being configured to connect the first space to an outlet ventilation duct; wherein the box connection space is provided with a second ventilation inlet and a second ventilation outlet, the second ventilation inlet is configured to connect the box connection space to an inlet ventilation duct, and the second ventilation outlet is configured to connect the box connection space to an outlet ventilation duct; wherein an entrance to the box connection space is provided through a second space, the second space including an airtight compartment and provided with a third ventilation inlet and a third ventilation outlet, the third ventilation inlet being configured to connect the second space to an inlet ventilation duct, the third ventilation outlet being configured to connect the second space to an outlet ventilation duct; and Wherein, the manhole and the secondary closure both comprise airtight covers, and wherein the airtight covers of the manhole and the airtight covers of the secondary closure are arranged one after another in a spaced-apart manner in the direction of travel.

2. The fuel tank according to claim 1, wherein The outlet ventilation duct is isolated from the tank holding space and is configured to guide outlet air from the first space, from the tank connection space, and from the second space to external air outside the tank holding space, respectively.

3. The fuel tank according to claim 1 or 2, wherein: The first space is configured to be ventilated via the first ventilation inlet and the first ventilation outlet at at least 10 air changes per hour.

4. The fuel tank according to claim 3, wherein The first space is configured to be ventilated via the first ventilation inlet and the first ventilation outlet at at least 30 air changes per hour.

5. The fuel tank according to any one of claims 1 to 4, wherein Ventilation includes suction-based ventilation.

6. The fuel tank according to any one of claims 1 to 5, wherein The first ventilation outlet and / or the outlet ventilation duct connected to the first ventilation outlet is provided with a gas detector configured to detect leakage from the fuel tank to the first space.

7. The fuel tank according to any one of claims 1 to 6, wherein The first space and the tank connection space at least partially share an outlet ventilation duct.

8. The fuel tank according to claim 7, wherein A branch connecting the outlet ventilation duct connected to the first ventilation outlet and the outlet ventilation duct connected to the second ventilation outlet is provided downstream of the first ventilation outlet and the second ventilation outlet.

9. The fuel tank according to any one of claims 1 to 8, wherein The secondary enclosure is provided with a drain pipe including a self-closing valve for draining condensed water from the first space using the self-closing valve.

10. The fuel tank according to claim 9, wherein The self-closing valve comprises a low-temperature self-closing valve.

11. The fuel tank according to any one of claims 1 to 10, wherein The access hole is configured to be vertically accessible from above the fuel tank when the fuel tank is in use.

12. The fuel tank according to any one of claims 1 to 10, wherein The access hole is configured to be accessible from above the fuel tank in a use position of the fuel tank at an angle relative to the vertical.

13. The fuel tank according to claim 11 or 12, wherein: The manhole is configured to be accessed at an angle of at most 45 degrees relative to vertical.

14. The fuel tank according to any one of claims 1 to 13, wherein The cover of the manhole and the cover of the secondary closure are arranged above each other in a vertical direction.

15. The fuel tank according to any one of claims 1 to 14, wherein At least the cover of the secondary enclosure includes a maintenance access door which is mounted to the secondary enclosure in a locking manner by means of bolts.

16. The fuel tank according to claim 15, wherein The cover of the secondary enclosure is mounted by means of a mounting flange and bolts installed through the mounting flange.

17. The fuel tank according to claim 15 or 16, wherein: At least one of the bolts is locked in the closed position by welding.

18. The fuel tank according to any one of claims 15 to 17, wherein The lid of the secondary closure includes separate locking means for locking the lid in the closed position.

19. The fuel tank according to any one of claims 1 to 18, wherein The secondary closure includes a dual plate configured to be mounted against a housing of the fuel tank and configured to at least partially conform to a shape of a surface of the housing of the fuel tank.

20. The fuel tank according to any one of claims 1 to 19, wherein The fuel tank is configured to hold liquefied gas.

21. The fuel tank according to claim 20, wherein The fuel tank is configured to hold hydrocarbon gas or ammonia.

22. The fuel tank according to any one of claims 1 to 21, wherein The fuel tank has an elongated form.

23. The fuel tank according to any one of claims 1 to 22, wherein: The fuel tank includes a tank connection space provided at an end portion of the fuel tank.

24. The fuel tank according to any one of claims 1 to 23, wherein The maximum height of the fuel tank is less than or equal to 1.5 times the maximum width of the fuel tank.

25. The fuel tank according to claim 24, wherein The maximum height of the fuel tank is in the range of 0.5 to 1.5 times the maximum width of the fuel tank.

26. The fuel tank according to any one of claims 1 to 25, wherein The maximum length of the fuel tank is in the range of 2 to 8 times the maximum diameter of the fuel tank, the maximum diameter being measured in a direction transverse to the longitudinal direction of the fuel tank.

27. The fuel tank according to any one of claims 1 to 26, wherein The fuel tank has at least partially the form of a body of revolution.

28. The fuel tank according to claim 27, wherein The longitudinal direction of the fuel tank extends in the direction of the axis of the rotating body.

29. The fuel tank according to any one of claims 1 to 28, wherein The fuel tank is configured to be placed on a support structure for supporting the fuel tank.

30. The fuel tank according to any one of claims 22 to 29, wherein In the use position of the fuel tank, the longitudinal direction of the fuel tank is arranged in a substantially horizontal direction.

31. The fuel tank according to any one of claims 1 to 30, wherein The volume of the fuel tank is between 100 and 3000m 3 within the range.

32. The fuel tank according to claim 31, wherein The volume of the fuel tank is between 300 and 2000m 3 within the range.

33. The fuel tank according to any one of claims 1 to 32, wherein The fuel tank has a capacity of at least 300m 3 .

34. The fuel tank according to any one of claims 1 to 33, wherein The secondary closure is disposed on an upper portion of the fuel tank, the upper portion extending 30 degrees on either side of a top centerline of the fuel tank, the top centerline being parallel to a longitudinal direction of the fuel tank.

35. The fuel tank according to any one of claims 1 to 34, wherein At least a portion of a meter of the fuel tank is disposed in the first space.

36. The fuel tank according to any one of claims 1 to 34, wherein No fuel tank instrumentation is arranged in the first space.

37. The fuel tank according to any one of claims 1 to 36, wherein At least a portion of a meter of the fuel tank is disposed in the tank connection space.

38. A fuel tank according to any one of claims 54 to 37, wherein The fuel tank instrument includes at least one of a liquid level gauge and a gas temperature measuring device.

39. The fuel tank according to any one of claims 1 to 38, wherein An inlet between the second space and the tank connection space is bolted.

40. The fuel tank according to any one of claims 1 to 39, wherein The tank connection space is configured to be accessible from an end or a side of the fuel tank.

41. The fuel tank according to any one of claims 1 to 40, wherein The tank connection space is configured to be accessible through the second space.

42. The fuel tank according to claim 41, wherein The second space and the tank connection space both include airtight covers, and wherein the airtight cover of the second space and the airtight cover of the tank connection space are disposed one after another in a spaced-apart manner in a traveling direction.

43. The fuel tank according to any one of claims 1 to 41, wherein The tank connection space is configured to be accessible from above the fuel tank.

44. A fuel tank according to any one of claims 1 to 43, wherein The fuel tank comprises a low temperature design.

45. A vessel, comprising: hull; deck; fuel tank, Characterized in that the fuel tank comprises the fuel tank according to any one of claims 1 to 44.

46. A vessel according to claim 45, wherein The fuel tank is disposed within the hull and below the deck.

47. A vessel according to claim 46, wherein The vessel comprises a second fuel tank below the deck, wherein the fuel tank and the second fuel tank are arranged side by side, and wherein the fuel tank and the second fuel tank at least partially share a common ventilation arrangement.

48. A vessel according to claim 47, wherein The fuel tank and the second fuel tank at least partially share the inlet ventilation duct and / or the outlet ventilation duct.

49. A vessel according to any one of claims 45 to 48, wherein At least one fuel tank is configured to be disposed on a support structure disposed in a tank holding space of the vessel for supporting the fuel tank.

50. A vessel according to any one of claims 45 to 49, wherein In the use position of the vessel, the longitudinal direction of the fuel tank is arranged in a substantially horizontal direction.

51. A vessel according to any one of claims 45 to 50, wherein The entire tank holding space is provided below the deck.

52. A vessel according to any one of claims 45 to 51, wherein Said vessels include vessels classified according to IGF or IGC codes.

53. A method in relation to a vessel, the vessel comprising: hull; deck; fuel tank, It is characterized by: The fuel tank comprises a fuel tank according to any one of claims 1 to 44, and The method comprises: isolating the tank connection space to form an airtight compartment housing a tank penetration and a tank valve for fuel; providing a secondary closure covering the manhole and defining a first space between the manhole and the secondary closure, the first space extending at least around and above the manhole; and The secondary closure is configured to form, when closed, an airtight compartment that isolates the first space from a tank holding space that surrounds the fuel tank, the tank connection space, and the secondary closure.

54. The method of claim 53, wherein: The method also includes ventilating the first space via the first ventilation inlet and the first ventilation outlet at at least 30 air changes per hour.

55. The method according to claim 53 or 54, wherein The method includes retaining liquefied gas in the fuel tank.

56. The method of claim 55, wherein: The method includes retaining hydrocarbon gas or ammonia in the fuel tank.

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