CN120246172A

CN120246172A - Tanks for storing and/or transporting liquefied gas cargoes used in ships

Info

Publication number: CN120246172A
Application number: CN202510008036.2A
Authority: CN
Inventors: 佛罗莱恩·巴迪恩; 尼古拉斯·勒鲁
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2024-01-03
Filing date: 2025-01-03
Publication date: 2025-07-04
Also published as: JP2025111391A; FR3157916A1; KR20250106707A

Abstract

The present invention relates to tanks for storing and/or transporting liquefied gas cargo for use in ships. The tank comprises a loading/unloading tower comprising M masts, M being an integer between 2 and 4, each mast extending along a vertical axis, N unloading pumps, N being an integer between 1 and 4 and comprising 1 and 4 and less than M, and a base at the lower end of the loading/unloading tower, characterized in that each of the N pumps is provided at the lower end of the loading/unloading tower, each of the N pumps being in line with the masts, and the base comprises an anchor device fixed to the N pumps and extending in a first horizontal plane, a vertical guide device for guiding each pump vertically with respect to the base, and a first holding arm for each mast extending from the anchor device to the masts along a first axis intersecting the first horizontal plane. The invention also relates to a vessel.

Description

Tank for storing and/or transporting liquefied gas cargo for a ship

Technical Field

The present invention relates to the field of vessels for transporting fluids, such as Liquefied Natural Gas (LNG). More particularly, the invention relates to the field of tanks equipped with such vessels, in which tank liquefied gas (e.g. liquid natural gas) is stored and which tank comprises a tower for loading/unloading liquefied natural gas, so that a fluid can be loaded into and/or unloaded from the tank.

Background

Known in the prior art are sealed and insulated tanks for storing liquefied gas on board a ship and equipped with a loading/unloading tower. The loading/unloading tower is typically suspended from the top wall of a support structure consisting of the inner hull of the vessel. The tank also has a support leg which is fixed to the support structure in the region of the bottom wall of the tank. The support legs are adapted to guide the vertical translational movement of the loading/unloading tower.

Such a tank may comprise a corrugated primary sealing membrane intended to be in contact with liquefied gas. Particularly in the case of deformations associated with large temperature variations, the corrugated sealing film includes a plurality of corrugations to increase the flexibility of the corrugated sealing film.

Hereinafter, the background of the invention and the invention itself are described using LNG as an example. However, the present invention is by no means limited thereto, and the present invention may be applied to other liquefied gases, liquefied petroleum gases, hydrogen, ammonia, as cited as non-limiting examples.

Such LNG-carrying vessels typically comprise four tanks with a total volume 174000m ³ for containing LNG cargo. The loading/unloading tower in each tank includes two unloading pumps, each associated with a mast, and each capable of unloading LNG by pumping the LNG through the mast. Each pump is typically offset relative to a vertical axis along which a mast associated with the pump extends. More precisely, each mast defines a perimeter in its axial projection on the bottom wall of the tank. The offset of the pump relative to the vertical axis of the mast means that the pump is disposed entirely outside the periphery. The term "pump" means a combination of an electric motor and a pump body configured to pump a fluid, in this case LNG, present in a tank.

The time to unload the vessel is typically about 12 to 14 hours.

A new generation ship may have three tanks for holding the same total cargo volume. Thus, each can has a larger volume. However, it is desirable to maintain the same unloading time as the time to unload a ship having four tanks.

It must be remembered that at sea, the liquefied gas storage tanks can exhibit sloshing due to the action of sea waves. These phenomena can be very severe inside the tank and can therefore generate significant forces in the tank, in particular on the equipment of the tank (for example loading/unloading towers and pump fixing elements).

One concept behind the invention is to add an additional unloading pump (i.e. the third unloading pump in the example) in the tank to increase the unloading flow. However, adding a third pump involves difficulties in integrating the additional pump into the tripod mast. In fact, in order for the pumps to function well, the distances between the pumps must be observed, these distances being defined by the pump suppliers. Furthermore, depending on the vessel, the loading/unloading tower may be located in the tank very close to the side wall of the tank, or conversely at a greater distance from this wall. Therefore, in view of these arrangement constraints and constraints related to sloshing phenomena, it is necessary to be able to install three pumps.

Disclosure of Invention

The present invention aims to alleviate some or all of the above problems by proposing a loading/unloading tower comprising two to four masts (preferably three masts) and one, two, three or four unloading pumps (the number of pumps being less than or equal to the number of masts), each unloading pump being arranged below a mast, the loading/unloading tower being equipped with an innovative foundation connected at the lower end of the three masts. In addition to providing an interface between the mast, the pump and the support legs fixed to the bottom wall of the tank, the innovative base prevents the horizontal movement of the pump, while enabling a vertical relative movement between the pump and the base caused by the thermal contraction effect of contact with the liquefied gas.

To this end, the object of the invention is a tank for a vessel for storing and/or transporting fluids, the tank comprising:

a loading/unloading tower comprising M masts, each mast extending along a vertical axis, M being an integer comprised between 2 and 4 and comprising 2 and 4;

a support leg fixed to the bottom wall of the tank;

n unloading pumps, N being an integer comprised between 1 and 4 and comprising 1 and 4 and less than or equal to M;

a base at the lower end of the loading/unloading tower and connected to the support leg.

According to the invention, each of the N unloading pumps is arranged at the lower end of the loading/unloading tower, each of the N unloading pumps being in line with and fluidly connected to the mast, the base comprising:

an anchoring device fixed to the N unloading pumps and extending in a first horizontal plane;

vertical guiding means for guiding each pump vertically with respect to the base;

A first retaining arm for each mast extending from the anchoring device to said mast along a first axis intersecting the first horizontal plane.

Advantageously, the anchoring means comprise at least one collar portion for each pump, the at least one collar portion being fixed to the upper portion of the pump, and a skirt extending from the at least one collar portion along the enclosure surface to at least one first height of the pump.

In the context of the present invention, a "mast" refers to a substantially vertical, substantially hollow structural portion of a loading/unloading tower that extends from the bottom to the top of a storage tank.

Furthermore, the mast can support a platform (or liquid dome) provided in the upper part of the loading/unloading tower. Furthermore, the diameter of the mast may be larger than the diameter of the pipe or conduit for the fluid (e.g. liquefied gas). Advantageously, each pump comprises at least one first guide element arranged at a first level of said pump, the vertical guide means comprising a second guide element for each pump, fixed to the skirt and having a shape complementary to the first guide element, the second guide element being vertically translatable with respect to the first guide element.

Advantageously, the base comprises a fixed zone extending in a second horizontal plane different from the first one and connecting the pairs of skirts of the three pumps.

Advantageously, the second horizontal plane is parallel to the first horizontal plane.

Advantageously, the base further comprises at least one structural connection between the fixing area and the anchoring means.

In one embodiment of the invention, each skirt comprises at least one lateral opening facing at least one first guide element, the second guide element being fixed on a respective opposite side of the at least one lateral opening.

In another embodiment, the at least one first guiding element comprises a collar fixed around the pump at a first height, the collar comprising at least one projection extending radially towards the skirt and a pin arranged on the at least one projection and extending vertically, the second guiding element comprising two parts connected to each other, the two parts comprising a channel provided with the pin.

Advantageously, at least one skirt comprises a plurality of stiffeners extending from an enclosing surface of the skirt, preferably in a vertical and/or horizontal direction.

Advantageously, the anchoring means are perforated in the first horizontal plane.

Advantageously, the base comprises a second retaining arm for each mast, extending from the anchoring device to said mast along a second axis intersecting the first horizontal plane and different from the first axis.

The invention also relates to a vessel comprising a hull forming a support structure and at least one such tank anchored to said support structure.

Drawings

These and other features and advantages of the invention will become more apparent on the basis of the following description, given with reference to the accompanying drawings provided by way of non-limiting example, in which:

Fig. 1 is a schematic cross-sectional view of a sealed and insulated tank for storing a fluid and equipped with a loading/unloading tower according to the present invention.

Fig. 2 is a perspective view of a tank loading/unloading tower according to one embodiment of the present invention.

Fig. 3 is a perspective view of a first embodiment of a base according to the present invention.

Fig. 4 is a perspective view of a first embodiment of a base according to the present invention.

Fig. 5 shows a guide element of a pump according to a first embodiment of the base of the invention.

Fig. 6 shows the guiding element from fig. 4 seen from a different angle.

Fig. 7 is a detailed view from below of the unloading tower, showing the guiding of the loading/unloading tower on the support legs.

Fig. 8 is a perspective view of a second embodiment of a base according to the present invention.

Fig. 9 shows a guide element of a pump according to a second embodiment of the base of the invention.

Fig. 10 is a perspective view of a third embodiment of a base according to the present invention.

Fig. 11 is a perspective view of a fourth embodiment of the present invention.

Fig. 12 is a perspective view of a base of a fourth embodiment of the present invention.

Fig. 13 is a schematic cross-sectional view of a ship tank and a quay for loading/unloading the tank according to the present invention.

Detailed Description

For clarity, the same elements have been given the same reference numerals in the different figures.

If the features, variations and embodiments of the invention that have been described or will be described in the following detailed description are not mutually incompatible or mutually exclusive, these features, variations and embodiments may be associated with each other in various combinations. In particular, if the choice of features is sufficient to confer technical advantages and/or to distinguish the invention from the prior art, variants of the invention are conceivable which comprise only the choice of features described below, apart from the other features described.

The present invention relates to a sealed and insulated tank for storing liquefied gas, which is equipped with a loading/unloading tower, so that liquefied gas can be loaded into and/or unloaded from the tank. As a non-limiting example, the liquefied gas may be in particular Liquefied Natural Gas (LNG).

The sealed and insulated tank 1 for storing liquefied gas is equipped with a loading/unloading tower 5, in particular capable of loading liquefied gas into the tank 1 and/or unloading liquefied gas from the tank 1. The liquefied gas may in particular be Liquefied Natural Gas (LNG), i.e. a gas mixture comprising mainly methane and one or more other hydrocarbons, such as ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane and a small proportion of nitrogen.

The tank 1 is anchored into a support structure 3 on the vessel. The support structure 3 is for example formed by a double hull of a vessel, but more generally may take the form of any type of rigid bulkhead with suitable mechanical properties. The tank 1 may be used for transporting liquefied gas or for containing liquefied gas used as fuel for propelling a ship.

In one embodiment, tank 1 is a membrane tank. In such a tank 1, each wall comprises, in order from the outside to the inside in the thickness direction of the wall, a secondary thermal insulation barrier 4 comprising an insulating element against the support structure 3, a secondary sealing film 2 anchored to the insulating element of the secondary thermal insulation barrier 4, a primary thermal insulation barrier 6 comprising an insulating element against the secondary sealing film 2 anchored to the insulating element of the primary thermal insulation barrier 6 and intended to be in contact with the fluid contained in the tank 1.

In fig. 1, the loading/unloading tower 5 is mounted near the rear wall 8 of the tank 1, which enables optimizing the amount of cargo that can be unloaded by the loading/unloading tower 5, given that the vessel is usually tilted aft using ballast in a specific manner.

The base 100, 200, 300, 400 anchoring and guiding the pump is located in the lower part of the loading/unloading tower. The base is described below.

Fig. 2 is a perspective view of a tank loading/unloading tower 5 according to one embodiment of the invention.

The loading/unloading tower 5 is suspended from the upper wall 9 of the support structure 3. In a preferred embodiment, the upper wall 9 of the support structure 3 comprises, in the vicinity of the rear wall 8, a space (not shown) of rectangular parallelepiped shape protruding upwards, called a liquid dome. The liquid dome is defined by front and rear transverse walls and two side walls extending vertically and protruding upwards from the upper wall 9. The liquid dome further comprises a horizontal cover 10, from which the loading/unloading tower 5 is suspended.

The loading/unloading tower 5 extends substantially over the entire height of the tank. The loading/unloading tower 5 comprises M masts, M being an integer between 2 and 4 (including 2 and 4), here three masts 11, 12, 13, each extending along a vertical axis and being fixed to each other by a cross beam 15. In other words, the loading/unloading tower comprises two, three or four masts. The term "tripod structure" is used when the tower 5 comprises three masts. Each of the masts 11, 12, 13 is hollow and passes through the liquid dome cover 10.

Advantageously, the masts 11, 12, 13 define together with the cross beam 15 a triangular cross-section prism.

The tank for storing and/or transporting fluids according to the present invention further comprises a support leg 14 fixed to the bottom wall of the tank. The storage and/or transport tank further comprises N discharge pumps 21, 22, 23, N being an integer between 1 and 4 (including 1 and 4) and less than or equal to M. In other words, the tank comprises one, two, three or four unloading pumps, the number of pumps being less than or equal to the number of masts. Finally, the tank comprises a base 200 at the lower end of the loading/unloading tower 5 and connected to the support legs 14. Hereinafter, the invention is described in the case where N is equal to 3 (that is to say, in the case of a tank comprising three unloading pumps, each associated with a mast), and M is equal to 3. In case the tank comprises only one unloading pump or two unloading pumps, the description of the invention is exactly the same. Also, where the tower includes two masts or three masts or four masts, the description of the invention is identical. In the case of two (or one) off-load pumps and three masts, one (or two) masts are not associated with a pump. The mast (or those two masts) maintains structural function without altering the features of the base described below. In this case, where the tower comprises four masts, the skilled person will appreciate that, thanks to the description of the invention, the foundation described below may be identical to the description below (that is to say, with three guiding means) or adapted to provide four guiding means in a similar manner as described below for three masts. Accordingly, the specification and drawings show three pumps and three masts, but the invention is not limited thereto.

According to the invention, three pumps 21, 22, 23 are each provided at the lower end of the loading/unloading tower 5, each of the three pumps 21, 22, 23 being in line with and fluidly connected to a mast 11, 12, 13. The physical and fluid connection between the pump and the mast is provided in a known manner, for example by means of a flange, the diameter of which is adapted to match the diameter of the outlet of the pump body and the diameter of the mast. In the case where one mast (or both masts) is not associated with a pump, no flange is present on the masts.

In the embodiments described below, the pump is connected to the mast by a connection member 500, enabling a fluid connection between the outlet of the pump and the mast to which the pump is connected. In this embodiment, the connecting member 500 has a cylindrical shape and has two ends, one of which faces the mast opening to which the connecting member is connected and the other of which faces the outlet opening of the pump. In other words, each of the ends of the connection member 500 cooperates with a pump or mast, respectively. The connection member 500 enables a fluid connection between the pump and the mast.

The two openings of the connecting part have different diameters. In these particular examples, the diameter of the pump-engaging opening of the connection member 500 is smaller than the diameter of the mast-engaging opening of the connection member 500.

The embodiment not shown suggests omitting the connecting member and replacing it with a spacer that can be adjusted to take into account the height at which the pump is located. This configuration is possible in particular when the outlet of the pump has the same diameter as the mast to which the pump is connected.

This arrangement makes it possible to reduce not only the weight of the loading/unloading tower but also the height of the connection connecting the upper part of the foundation to the mast and thus the impact of sloshing effects associated with the movement of the liquid in the tank.

The foundation according to the invention comprises an anchoring device fixed to the three pumps and extending in a first horizontal plane (when there are at least two pumps, the anchoring device extends between two adjacent pumps), means for guiding each pump vertically with respect to the foundation, and a first retaining arm for each mast, which extends from the anchoring device to said mast along a first axis intersecting the first horizontal plane. Details of the innovative base are described below.

Fig. 3 is a perspective view of a first embodiment of a base 100 according to the present invention. As can be seen in fig. 3, three pumps 21, 22, 23 are each provided at the lower end of the loading/unloading tower 5, each of the three pumps 21, 22, 23 being in line with and fluidly connected to a mast 11, 12, 13. In other words, pump 21 is located below mast 11, pump 22 is located below mast 12, and pump 23 is located below mast 13. From what has been explained above, the person skilled in the art will understand that one or both pumps may be omitted without changing the core of the invention. The flange connection connects the upper end of the pump to the lower end of the mast. The three masts 11, 12, 13 and the cross beam 15 project into the plane of the bottom wall forming a triangle, and the pumps 21, 22, 23 are arranged at the respective vertices of the triangle.

Since each pump is positioned below the mast, the minimum distance required between the pumps is met, and the loading/unloading tower in the tank can be located close to the side wall of the tank or away from the side wall. The presence of three pumps in a tank enables a greater unloading flow than the same tank with two pumps. Thus, for a tank of larger volume, the same unloading time as that of a conventional tank of smaller volume can be maintained. Furthermore, the addition of a third pump to the tank makes it possible to dispense with the presence of a retractable emergency pump to alleviate the failure of one of the pumps.

According to the invention, the foundation 100 comprises an anchoring device 110 fixed to the three pumps 21, 22, 23 and extending between two adjacent pumps in a first horizontal plane P1. More precisely, each pump is equipped with a fixing lug 31 (preferably at least two fixing lugs) provided at the upper end of the pump. The anchoring device 110 is fixed to the pump by the fixing lugs 31. Thus, the anchoring device 110 provides a connection (here a direct connection) of the pumps in pairs in the same plane P1. The anchoring means defines an upper portion of the base and together with a lower portion of the base, which will be described in detail below, is capable of absorbing forces caused by shaking. Such a configuration ensures the mechanical strength of the base, although the impact of the liquefied gas on the tower 5 due to sloshing causes hydrodynamic forces.

The base comprises vertical guiding means 111 for guiding each pump vertically with respect to the base 100. The vertical guiding means enable a vertical relative movement between the pump and the base caused by the effect of thermal contraction in contact with the liquefied gas. By associating the anchoring means 110 with the vertical guiding means 111, the base 100 prevents the horizontal movement of the pump. Thus, the pump and mast of the tower do not have the freedom of horizontal translational movement, so that all components remain in place despite the jolt impact. However, a freedom of vertical translational movement is enabled between the pump and the base, such that the pump body, which is typically made of aluminum, is able to thermally shrink with respect to the base, which is made of, for example, stainless steel.

Finally, the base 100 comprises a first retaining arm 112 for each mast, which extends from the anchoring device 110 to said mast along a first axis Z1 intersecting the first horizontal plane P1. The retaining arm transfers force from the mast to the base. As will be apparent below, the base is connected to the support structure by support legs 14, the retaining arms constituting a force transmission path between the mast and the support structure.

Fig. 4 is a perspective view of a first embodiment of a base according to the present invention. In this figure, only the base 100 is shown (that is, the mast, pump, support legs are not shown).

The anchoring means 110 comprise at least one collar portion 113 for each pump, which is fixed to the upper part of the pump, and a skirt 114 extending from the at least one collar portion along an enclosing surface 115 over at least a first height h1 (this height being shown in fig. 3) of the pump.

As shown in fig. 3, the collar portion 113 is fixed to the fixing lug 31 of the pump. In the first embodiment shown in fig. 3 and 4, the skirt 114 extends vertically from the collar portion to the lower portion of the pump. As described below, the skirt acts as a support for the vertical guide in addition to contributing to the mechanical strength of the base.

The base comprises a fixed area 118 extending in a second horizontal plane P2 different from the first plane P1 and connecting pairs of skirts of three pumps. Advantageously, the second horizontal plane P2 is parallel to the first horizontal plane P1. The fixed area 118 defines a lower portion of the base, and the fixed area 118 together with an upper portion of the base achieves good mechanical strength of the base in a confined environment for liquefied gas transport.

Advantageously, the base 100 further comprises at least one structural connection 119 between the fixing region 118 and the anchoring device 110. Although not shown, one or more other structural connectors 119 may connect the securing region 118 and the anchor 110, for example, at an opening in a central portion of the base. The structural connection 119 stiffens between the upper and lower portions of the base to enable better distribution of the forces exerted at the first horizontal plane.

Fig. 5 shows a pump guiding element according to a first embodiment of the base of the invention.

In this embodiment, each pump comprises at least one first guiding element 116 arranged at a first height h1 of the pump. The vertical guiding means comprise a second guiding element 117 for each pump, fixed to the skirt 114 and having a shape complementary to the first guiding element 116. The second guide element is vertically translatable relative to the first guide element.

More precisely, in this embodiment, the first guide element 116 has two L-shaped ends 126. The second guide element 117 comprises two parallel flanges 127 which are spaced apart by the width of the first guide element 116 between the two ends 126 of the first guide element 116. The double L-shape formed by the two flanges 127 mates with the end 126 of the guide element 116. These complementary shapes provide freedom of vertical translational movement and block any horizontal translational movement.

Advantageously, each skirt 114 comprises at least one lateral opening 140 facing the first guide element 116, and advantageously the second guide element 117 has an end fixed to a respective opposite side of the lateral opening 140. The opening 140 facilitates the mounting and securing of the second guide element 117.

Fig. 6 shows the guiding element 117 from fig. 5 seen from a different angle. When in place, the inner surface 128 is a surface having a shape complementary to the first guide element 116. These inner surfaces may be provided with sliding rails 129. The slide rail provides contact and relative movement between the first guide element 116 and the second guide element 117. The rail 129 may be made of HDPE (high density polyethylene).

In a conventional manner, the tank has support legs 14 which are fixed to the support structure in the region of the bottom wall of the tank. The support legs are adapted to guide the vertical translational movement of the loading/unloading tower. The support leg 14 has a circular cross-sectional shape of revolution and has a frustoconical lower portion 54 connected to the cylindrical upper portion at the smaller diameter end of the frustoconical lower portion. The larger diameter bottom of the frustoconical portion bears against the bottom wall of the support structure. The frustoconical lower portion 54 generally extends through the thickness of the bottom wall of the canister, extending beyond the primary sealing membrane. The cylindrical upper part is closed in a sealing manner by a circular plate. The primary and secondary sealing membranes are sealingly connected to the frustoconical lower portion 54.

The loading/unloading tower 5 comprises guiding means fixed on the lower surface of the base 100, which cooperate with support legs 14 fixed to the bottom wall of the support structure. Such guiding means are intended to enable the loading/unloading tower 5 to be moved in the height direction of the tank with respect to the supporting legs 14, so that the loading/unloading tower 5 can contract or expand according to the temperature to which it is subjected, while at the same time preventing a horizontal movement of the base 100 of the loading/unloading tower 5 by means of the guiding elements 57, 59.

The base according to the invention is thus provided with an upper part (anchoring means) substantially in plane P1 and a lower part (guiding means) substantially in plane P2, the upper and lower parts being connected to each other by a skirt and structural connection, if any. The upper part anchors the pump and provides a connection to the mast, while the lower part guides the pump and the mast. This two-layer structure enables three pumps to be arranged in the tank and meets the mechanical strength criteria required to support the forces applied to the loading/unloading tower and the equipment of the loading/unloading tower.

Fig. 8 is a perspective view of a second embodiment of a base according to the present invention. The base 200 comprises the same elements as the base 100, i.e. comprises an anchoring device 120 fixed to the three pumps 21, 22, 23 and extending between two adjacent pumps in a first horizontal plane P1, a vertical guiding device 121 for guiding each pump with respect to the base 200, and a first retaining arm 122 for each mast extending from the anchoring device 120 to said mast along a first axis Z1 intersecting the first horizontal plane P1.

In this embodiment, the collar for each pump takes the form of a semicircle and surrounds the pump between two fixing lugs 31 of the pump which are diametrically opposite with respect to the pump body. The skirt 124 descends along the pump at a distance along the enclosure surface 125. Collar 123 and skirt 124 form a housing half for the pump. The three housing halves connect the anchoring means extending in the horizontal plane P1 and the fixing area extending in the plane P2, thereby providing rigidity of the base. Optionally, the base may include structure (not shown in fig. 8) between the securing region 128 and the anchoring device 120 to strengthen the structure of the base and enable transmission of forces from the upper portion to the lower portion of the base. In the same alternative, the base may include structure (not shown) between the fixing area and the skirt to strengthen the structure of the base and enable transmission of force from the upper portion to the lower portion of the base.

In a second embodiment, the anchoring device 120 is perforated in the first horizontal plane P1. In contrast to the anchoring device 110, which extends in material continuity in plane P1 between the collars, the anchoring device 120 comprises at least three main structures extending in plane P1 and connecting pairs of collars 123. As shown in fig. 8, the anchoring device 120 may advantageously comprise at least one additional structure for each pump, extending in the plane P1 between the two main structures, to strengthen the structure of the anchoring device. Accordingly, the anchor 120 comprises less material than the anchor 110, thereby reducing weight on the vessel.

The first guide element 136 comprises a collar 150 fixed around the pump at a first height h 1. Collar 150 includes at least one projection 151 extending radially toward skirt 124 and a vertically extending pin 152 disposed on projection 151. The second guiding element 137 comprises two parts 153, 154 connected to each other, which two parts 153, 154 comprise a channel 155 provided with a pin 152. The channel 155 has a shape complementary to the pin 152. The portion 153 is fixed to the skirt. The two portions 153, 154 may be made of HDPE. The two sections may be secured to one another by placing and clamping plate 158 over section 154 and nut-and-bolt assemblies 156, 157, as shown in fig. 9. Thus, the pin 152 fixed to the pump is free to move in translation in the channel 155 of the second guide element 137 fixed to the base, to achieve a vertical relative movement between the pump and the base due to thermal contraction.

It may be noted that the first guide element 116 and the second guide element 117 have been described with reference to the first embodiment, and the first guide element 136 and the second guide element 137 have been described with reference to the second embodiment. However, if the guide elements 116, 117 are applied to the second embodiment and the guide elements 136, 137 are applied to the first embodiment, this will not be beyond the scope of the present invention, as would be realized by a person skilled in the art after reading the description of the present invention.

Fig. 10 is a perspective view of a third embodiment of a base according to the present invention. The base 300 comprises the same elements as the base 200, i.e. comprises an anchoring device 130 fixed to the three pumps 21, 22, 23 and extending between two adjacent pumps in a first horizontal plane P1, a vertical guiding device 131 for guiding each pump vertically with respect to the base 300, and a first retaining arm 132 for each mast extending from the anchoring device 130 to said mast along a first axis Z1 intersecting the first horizontal plane P1.

In this embodiment, the collar 133 for each pump takes the form of a semicircle and surrounds the pump between its three fixing lugs 31. The skirt 134 descends along the pump at a distance along the enclosure surface 135. The collar 133 and skirt 134 form part of the housing for the pump. The three housing parts connect the anchoring means extending in the horizontal plane P1 and the fixing area extending in the plane P2, resulting in a stiffness of the base. In the case where one (or both) pumps are omitted, the base remains identical and the collar 133 and skirt 134 form part of the housing with no pump inside. Obviously, in this case, there is no flange in the lower part of the mast, nor is there a fixing lug. Optionally, the base may include structure (not shown in fig. 10) between the securing region 138 and the anchoring device 130 to strengthen the structure of the base and enable transmission of forces from the top to the bottom of the base. Optionally, the base may also include structure (not shown) between the securing region and the skirt to strengthen the structure of the base and enable transmission of forces from the upper portion to the lower portion of the base.

In the third embodiment and in a similar manner to the second embodiment, the anchoring device 130 is perforated in the first horizontal plane P1. Thus, the anchoring device 130 comprises less material than the anchoring device 110, which reduces the weight on the vessel.

Fig. 11 and 12 are perspective views of a fourth embodiment of the present invention. Note that in fig. 12, only the base 400 is shown (that is, the mast, pump, support legs are not shown).

The base 400 comprises the same elements as the base 100, i.e. an anchoring device 410 fixed to the three pumps 21, 22, 23 (the third pump 23 is not visible in fig. 11).

The anchoring means 410 extend between two adjacent pumps in a first horizontal plane P1. The base 400 further comprises vertical guiding means 411 for guiding each pump vertically with respect to the base 400, and at least one first retaining arm 412 for each mast extending from the anchoring means 120 to said mast along a first axis Z1 intersecting the first horizontal plane P1.

The base comprises a fixing zone which extends in a second horizontal plane P2 different from the first horizontal plane P1 and connects here a pair of skirts of three pumps.

The fastening region is perforated here.

Advantageously, the second horizontal plane P2 is parallel to the first horizontal plane P1. The fixed area defines the lower portion of the base 400 and, together with the upper portion of the base, achieves good mechanical strength of the base in a confined environment for transporting liquefied gas.

Thus, the base according to the invention has an upper portion (anchoring means 410) substantially in plane P1 and a lower portion (guiding means 411) substantially in plane P2, the upper and lower portions being connected to each other by a skirt 424 and structural connection, if any.

The upper part of the foundation anchors the pump and provides a connection to the mast, while the lower part guides the pump and the mast. This two-layer structure enables three pumps to be arranged in the tank and meets the mechanical strength criteria required to withstand the forces applied to the loading/unloading tower and the equipment of the loading/unloading tower.

In this embodiment, the anchoring device 410 is perforated at the center of the anchoring device. The anchoring means here take the form of triangular openings with a retaining arm for the mast at each vertex.

In this embodiment, the anchoring device 410 for each pump comprises at least one collar portion 423 for each pump, which is fixed to the upper portion of the pump, and a skirt 424 extending from the at least one collar portion on the enclosing surface 425 to at least a first height of the pump.

Skirt 424 extends vertically from collar portion 423 to a lower portion of the pump. The skirt 424 serves to support the vertical guide in addition to contributing to the manual strength of the base 400.

In this embodiment, the collar portion 423 takes the form of a semicircle, and the collar portion 423 surrounds the pump between two fixing lugs 431 of the pump that are diametrically opposed with respect to the pump body.

The skirt 424 descends along the pump at a distance along the enclosure surface 425. Collar portion 423 and skirt 424 form a housing half for the pump.

In this embodiment, three housing halves around each pump connect an anchor 410 extending in the horizontal plane P1 and a fixed area extending in the plane P2, resulting in rigidity of the base 400.

The base optionally includes struts between the anchor 410 and a fixed region extending in plane P2 to strengthen the structure of the base and enable transmission of forces from the upper portion to the lower portion of the base.

Optionally, the base may also include struts (not shown) between the securing region and the skirt to strengthen the structure of the base and enable transmission of forces from the upper portion to the lower portion of the base. Thus, such a configuration makes it possible to ensure the mechanical strength of the base, although the impact of the liquefied gas on the tower 5 due to sloshing causes hydrodynamic forces.

Here, the anchoring device 410 is perforated in a first horizontal plane P1 and comprises at least three main struts which extend in the plane P1 and connect pairs of collars 413.

As shown in fig. 11 and 12, the base 400 advantageously includes at least one additional strut extending between two adjacent skirts 424. The additional strut 600 here extends in a plane parallel to the plane P1, in particular in the plane P2 of the fastening region.

For each of the embodiments of the present invention, the skirt may comprise a plurality of stiffeners 160, the stiffeners 160 preferably extending from the enclosing surface of the skirt in a vertical and/or horizontal direction. These stiffeners stiffen the skirt.

Furthermore, the base may comprise a second retaining arm 212, 222, 232 for each mast extending from the anchoring device to said mast along a second axis Z2 intersecting the first horizontal plane P1 and different from the first axis Z1. The second retaining arm for each mast ensures a better distribution of forces between the mast and the base.

As shown in fig. 4 and 12, each retaining arm may terminate in two rings 165 around the mast, with each retaining arm being associated with the mast to retain the mast. Alternatively, each retaining arm may terminate in a single ring 165. Alternatively, each retaining arm may terminate in a retaining cylinder that is intended to receive a portion of the mast.

In the case where the base comprises two retaining arms for each mast, one or more retaining rings or cylinders are connected to the two retaining arms.

Likewise, the base may also include a transverse stiffener 166 extending in a horizontal plane, with two retaining arms associated with the mast. These transverse stiffeners 166 impart additional rigidity to the base at the retaining arms.

Fig. 13 is a schematic cross-sectional view of a tank according to the invention of a vessel 70 and a quay for loading/unloading the tank. The cross-section of the vessel 70 shows a sealed and insulated tank 71 having a generally prismatic shape mounted in a double hull 72 of the vessel. The wall of the tank 71 comprises a primary sealing membrane intended to be in contact with the liquefied gas contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the double hull 72 of the vessel, and two heat insulating barriers arranged between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull 72, respectively.

In a manner known per se, the loading/unloading pipe 73 arranged on the top deck of the vessel can be connected to a sea or port terminal by means of suitable connectors to transfer cargo of LNG from the tank 71 or into the tank 71.

Fig. 13 shows an example of a marine terminal comprising a loading and/or unloading station 75, an underwater pipeline 76 and a land facility 77. The loading and unloading station 75 is a fixed offshore facility comprising a mobile arm 74 and a tower 78 supporting the mobile arm 74. The traveling arm 74 carries a bundle of insulated flexible tubes 79 that can be connected to the load/unload conduit 73. The directional movement arm 74 is adaptable to vessels of all sizes. A connecting conduit, not shown, extends inside the tower 78. The loading and unloading station 75 enables loading and unloading of the vessel 70 from the land facility 77 or to the land facility 77. Land facility 77 includes a liquefied gas storage tank 80 and a connection pipe 81 connected to loading or unloading station 75 by a submarine pipeline 76. The underwater piping 76 enables the liquefied gas to be transferred over a large distance (e.g., 5 km) between the loading or unloading station 75 and the land facility 77, which enables the vessel 70 to maintain a large distance from shore during loading and unloading operations.

Pumps on board the vessel 70 and/or pumps equipped with land facilities 77 and/or pumps equipped with loading and unloading stations 75 are used to generate the pressure required to transfer the liquefied gas.

While the invention has been described in connection with a number of specific embodiments, it is evident that the invention is in no way limited to these embodiments and that the invention encompasses all technical equivalents and combinations of the means described, if such means fall within the scope of the invention.

Use of the verb "to comprise" or "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

It will be more generally apparent to those skilled in the art that various modifications can be made to the embodiments described above in light of the teachings just disclosed. In the following claims, the terms used should not be construed to limit the claims to the embodiments described in the specification, but should be construed to include all equivalents to which the claims are intended to cover by their expression, which equivalents will be apparent to those skilled in the art based on their general background knowledge.

Claims

1. Tank for a vessel for storing and/or transporting a fluid, the tank comprising:

-a loading/unloading tower (5) comprising M masts (11, 12, 13), each mast extending along a vertical axis, M being an integer comprised between 2 and 4 and comprising 2 and 4;

-support legs (14) fixed to the bottom wall of the tank;

-N unloading pumps (21, 22, 23), N being an integer comprised between 1 and 4 and comprising 1 and 4 and less than or equal to M;

-a base (100, 200, 300) located at the lower end of the loading/unloading tower (5) and connected to the support leg (14);

The tank being characterized in that each of the N unloading pumps (21, 22, 23) is arranged at the lower end of the loading/unloading tower (5), each of the N unloading pumps being in line with and fluidly connected to a mast (11, 12, 13),

And, the base (100, 200, 300) comprises:

-an anchoring device (110, 120, 130) fixed to the N unloading pumps (21, 22, 23) and extending in a first horizontal plane (P1);

-vertical guiding means (111, 121, 131) for guiding each pump vertically with respect to the base (100, 200, 300);

-a first retaining arm (112, 122, 132) for each mast extending from the anchoring device (110, 120, 130) to the mast along a first axis (Z1) intersecting the first horizontal plane (P1).

2. The canister of claim 1, wherein the anchoring means (110, 120, 130) comprises at least one collar portion (113,123,133) for each pump, the at least one collar portion being fixed to an upper portion of the pump, and a skirt (114, 124, 134) extending from the at least one collar portion to at least one first height (h 1) of the pump along an enclosure surface (115, 125, 135).

3. Tank according to claim 2, wherein each pump comprises at least one first guide element (116, 136) provided at the first height (h 1) of the pump, wherein the vertical guide means comprise a second guide element (117,137) for each pump, fixed to the skirt and having a shape complementary to the first guide element, which is vertically translatable with respect to the first guide element.

4. A tank according to claim 2 or 3, wherein the base comprises a fixing area (118,128,138) extending in a second horizontal plane (P2) different from the first horizontal plane (P1) and connecting pairs of skirts of three pumps.

5. Can of claim 4, wherein the second horizontal plane (P2) is parallel to the first horizontal plane (P1).

6. Tank according to claim 4 or 5, wherein the base (100, 200, 300) further comprises at least one structural connection (119,129,139) between the fixing area (118,128,138) and the anchoring means (110, 120, 130).

7. A tank according to any one of claims 2 to 5 in combination with claim 3, wherein each skirt (114) comprises at least one lateral opening (140) facing the at least one first guide element (116), the second guide element (117) being fixed on a respective opposite side of the at least one lateral opening (140).

8. A tank according to any one of claims 2 to 5 in combination with claim 3, wherein the at least one first guiding element (136) comprises a collar (150) fixed around the pump at the first height (h 1), the collar (150) comprising at least one projection (151) extending radially towards the skirt (124) and a pin (152) provided on the at least one projection (151) and extending vertically, the second guiding element (137) comprising two portions (153,154) connected to each other, the two portions comprising a channel (155) provided with the pin (152).

9. Can of any one of claims 2 to 8, wherein at least one skirt (114, 124, 134) comprises a plurality of stiffeners (160) extending from the enclosing surface of the skirt, preferably in a vertical and/or horizontal direction.

10. Can of any one of claims 1 to 9, wherein the anchoring means (120, 130) are perforated in the first horizontal plane (P1).

11. Tank according to any one of claims 1 to 10, wherein the base comprises a second retaining arm (212, 222, 232) for each mast, which extends from the anchoring device to the mast along a second axis (Z2) intersecting the first horizontal plane (P1) and different from the first axis (Z1).

12. Vessel comprising a hull forming a support structure and at least one tank according to any of claims 1 to 11 anchored to the support structure.