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

Abstract

The invention relates to a tank for storing and / or transporting liquefied gas cargo for a ship. 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, including 1 and 4 and less than M; and a base located 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 is in line with the mast, and the base comprises: anchoring means fixed to the N pumps and extending in a first horizontal plane; vertical guide means for vertically guiding each pump relative to the base; and a first retaining arm for each mast, the first retaining arm extending from the anchoring means to the mast along a first axis intersecting a first horizontal plane. The invention also relates to a ship.

Description

Field of the Invention

[0001] The present invention relates to the field of ships for transporting fluids such as liquefied natural gas (LNG). More specifically, the present invention relates to the field of tanks equipped on such ships, in which liquefied gas such as liquefied natural gas is stored, and the tank includes a tower for loading / unloading liquefied natural gas, so as to be able to load the fluid into the tank and / or unload the fluid from the tank. Background Art

[0002] It is known in the prior art a sealed and thermally insulated tank for storing liquefied gas on a ship and equipped with a loading / unloading tower. The loading / unloading tower is usually suspended from the top wall of a support structure which consists of the inner hull of the ship. The tank also has support legs 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.

[0003] Such a tank may include a corrugated main sealing membrane intended to be in contact with the liquefied gas. In particular, in the case of deformations associated with large temperature variations, the corrugated sealing membrane includes a plurality of corrugations to increase the flexibility of the corrugated sealing membrane.

[0004] Hereinafter, LNG is used as an example to describe the background of the present invention and the present invention itself. However, the present invention is in no way limited thereto, and the present invention can be applied to other liquefied gases cited as non-limiting examples, such as liquefied petroleum gas, hydrogen, and ammonia.

[0005] Such an LNG carrier usually includes four tanks with a total volume of 174000 m 3 for accommodating the LNG cargo. The loading / unloading tower in each tank includes two unloading pumps, each unloading pump being associated with a mast, and each unloading pump being able to unload LNG by pumping the LNG through the mast. Each pump is usually offset with respect to the vertical axis along which the mast associated with the pump extends. More precisely, in the axial projection of each mast on the bottom wall of the tank, each mast defines a perimeter. The offset of the pump with respect to the vertical axis of the mast means that the pump is completely set outside the perimeter. The term "pump" refers to a combination consisting of an electric motor and a pump body which is configured to suck the fluid, in this case the LNG present in the tank.

[0006] The time for unloading the ship is usually about 12 to 14 hours.

[0007] A new generation of ships may have three tanks for accommodating the same total cargo volume. Thus, each tank has a larger volume. However, it is desired to maintain the same unloading time as that for unloading a ship with four tanks.

[0008] It must be remembered that, at sea, due to the action of the waves, the liquefied gas storage tank will experience cargo sloshing phenomena. These phenomena can be very violent inside the tank and can thus generate significant forces in the tank, especially on the equipment of the tank (such as the loading / unloading tower and the pump fixing elements).

[0009] One idea behind the present invention is to add an additional unloading pump in the tank (i.e., the third unloading pump in the example) to increase the unloading flow rate. However, adding the third pump involves difficulties in integrating this additional pump into the tripod mast. In fact, in order for the pumps to operate well, the distances between the pumps must be observed, which are defined by the pump supplier. In addition, depending on the ship, the position of the loading / unloading tower in the tank can be very close to the side wall of the tank or, conversely, located at a greater distance from this wall. Therefore, taking into account these layout constraints and the constraints related to the sloshing phenomena, it must be possible to install three pumps. Summary of the Invention

[0010] The present invention aims to alleviate some or all of the above problems by proposing a loading / unloading tower that includes 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, and the loading / unloading tower being equipped with an innovative base connected to the lower ends of the three masts. In addition to providing an interface between the masts, the pumps, and the support legs fixed to the bottom wall of the tank, the innovative base prevents the horizontal movement of the pumps while enabling vertical relative movement between the pumps and the base caused by the thermal contraction effect of contact with the liquefied gas.

[0011] To this end, the object of the present invention is a tank for storing and / or transporting fluids for a ship, the tank comprising:

[0012] · A loading / unloading tower that includes M masts, each mast extending along a vertical axis, M being an integer between 2 and 4 inclusive;

[0013] · Support legs fixed to the bottom wall of the tank;

[0014] · N unloading pumps, N being an integer between 1 and 4 inclusive and less than or equal to M;

[0015] · A base located at the lower end of the loading / unloading tower and connected to the support legs.

[0016] According to the present invention, each of the N unloading pumps is arranged at the lower end of the loading / unloading tower, each of the N unloading pumps is in line with a mast and is fluidly connected to the mast, and the base comprises:

[0017] · An anchoring device that is fixed to N unloading pumps and extends in a first horizontal plane;

[0018] · Vertical guiding means for vertically guiding each pump relative to the base;

[0019] · A first holding arm for each mast, which extends from the anchoring device to the mast along a first axis intersecting the first horizontal plane.

[0020] Advantageously, the anchoring device includes at least one collar portion and a skirt for each pump, the at least one collar portion being fixed to the upper part of the pump, and the skirt extending from the at least one collar portion along an enclosing surface to at least a first height of the pump.

[0021] In the context of the present invention, a "mast" refers to a generally vertical and substantially hollow structural part of a loading / unloading tower that extends from the bottom to the top of a storage tank.

[0022] Furthermore, the mast can support a platform (or liquid dome) provided in the upper part of the loading / unloading tower. In addition, the diameter of the mast can be greater than the diameter of a pipe or conduit for a fluid (such as liquefied gas). Advantageously, each pump includes at least one first guiding element provided at a first height of the pump, and the vertical guiding means includes a second guiding element for each pump, the second guiding element being fixed to the skirt and having a shape complementary to that of the first guiding element, and the second guiding element being capable of vertically translating relative to the first guiding element.

[0023] Advantageously, the base includes a fixing area that extends in a second horizontal plane different from the first horizontal plane and connects the paired skirts of three pumps.

[0024] Advantageously, the second horizontal plane is parallel to the first horizontal plane.

[0025] Advantageously, the base further includes at least one structural connection member between the fixing area and the anchoring device.

[0026] In one embodiment of the present invention, each skirt includes at least one lateral opening facing at least one first guiding element, and the second guiding element is fixed on the corresponding opposite side of the at least one lateral opening.

[0027] In another embodiment, at least one first guiding element includes a collar fixed around the pump at a first height, the collar including at least one protrusion radially extending towards the skirt and a pin provided on the at least one protrusion and extending vertically, and the second guiding element includes two parts connected to each other, the two parts including a channel provided with a pin.

[0028] Advantageously, at least one skirt includes a plurality of stiffeners that extend from the enclosing surface of the skirt, preferably extending from the enclosing surface of the skirt in a vertical direction and / or a horizontal direction.

[0029] Advantageously, the anchoring device is perforated in a first horizontal plane.

[0030] Advantageously, the base includes a second retaining arm for each mast, the second retaining arm extending from the anchoring device to the mast along a second axis that intersects the first horizontal plane and is different from the first axis.

[0031] The present invention also relates to a ship that includes a hull forming a support structure and at least one such tank anchored to the support structure. Description of the Drawings

[0032] These features and advantages of the present invention, as well as other features and advantages, will become more apparent based on the following description given with reference to the drawings provided by way of non-limiting examples, in which:

[0033] Figure 1 is a schematic cross-sectional view of a sealed and thermally insulated tank for storing fluids and equipped with a loading / unloading tower according to the present invention.

[0034] Figure 2 is a perspective view of the loading / unloading tower of a tank according to an embodiment of the present invention.

[0035] Figure 3 is a perspective view of a first embodiment of the base according to the present invention.

[0036] Figure 4 is a perspective view of a first embodiment of the base according to the present invention.

[0037] Figure 5 shows the guiding element of the pump of the first embodiment of the base according to the present invention.

[0038] Figure 6 shows the guiding element seen from different angles from Figure 4 of.

[0039] Figure 7 is a detailed view seen from below the unloading tower, showing the guiding of the loading / unloading tower on the support legs.

[0040] Figure 8 is a perspective view of a second embodiment of the base according to the present invention.

[0041] Figure 9 shows the guiding element of the pump of the second embodiment of the base according to the present invention.

[0042] Figure 10 is a perspective view of a third embodiment of a base according to the present invention.

[0043] Figure 11 is a perspective view of a fourth embodiment of the present invention.

[0044] Figure 12 is a perspective view of a base of a fourth embodiment of the present invention.

[0045] Figure 13 is a schematic cross-sectional view of a marine tank and a terminal for loading / unloading said tank according to the present invention. Detailed Description

[0046] For the sake of clarity, the same elements have the same reference numerals in different figures.

[0047] If the features, variations, and embodiments of the present invention that have been described or will be described in the following detailed description are not mutually incompatible or exclusive of each other, then these features, variations, and embodiments can be associated with each other in various combinations. In particular, if the selection of features is sufficient to confer a technical advantage and / or to distinguish the present invention from the prior art, then it is contemplated that a variation of the present invention includes only the selection of the features described below that are separate from the other features described.

[0048] The present invention relates to a sealed and thermally insulated tank for storing liquefied gas, the sealed and thermally insulated tank being equipped with a loading / unloading tower so as to be able to load liquefied gas into the tank and / or unload liquefied gas from the tank. As a non-limiting example, the liquefied gas can in particular be liquefied natural gas (LNG).

[0049] Figure 1 is a schematic cross-sectional view of a sealed and thermally insulated tank for storing a fluid and equipped with a loading / unloading tower according to the present invention.

[0050] The sealed and thermally insulated tank 1 for storing liquefied gas is equipped with a loading / unloading tower 5 and is in particular able to load liquefied gas into the tank 1 and / or unload liquefied gas from the tank 1. The liquefied gas can in particular be liquefied natural gas (LNG), i.e., a gas mixture mainly comprising methane and one or more other hydrocarbons (such as ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, and a small proportion of nitrogen).

[0051] The tank 1 is anchored in a support structure 3 on a ship. The support structure 3 is formed, for example, by the double hull of the ship, but more generally can take the form of any type of rigid bulkhead having appropriate mechanical properties. The tank 1 can be used for transporting liquefied gas or for containing liquefied gas used as fuel for propelling the ship.

[0052] In one embodiment, tank 1 is a membrane tank. In such a tank 1, each wall, in the thickness direction of the wall, sequentially includes a secondary thermal insulation barrier 4, a secondary sealing film 2, a primary thermal insulation barrier 6, and a primary sealing film 7 from the outside to the inside. The secondary thermal insulation barrier includes insulating elements against a support structure 3. The secondary sealing film is anchored to the insulating elements of the secondary thermal insulation barrier 4. The primary thermal insulation barrier includes insulating elements against the secondary sealing film 2. The primary sealing film is anchored to the insulating elements of the primary thermal insulation barrier 6 and is intended to be in contact with the fluid contained in tank 1.

[0053] In Figure 1 it, a loading / unloading tower 5 is installed near the rear wall 8 of the tank 1. Assuming that the ship usually uses ballast to tilt towards the stern in a specific manner, this enables optimizing the quantity of goods that can be unloaded by the loading / unloading tower 5.

[0054] Bases 100, 200, 300, 400 for anchoring and guiding pumps are located in the lower part of the loading / unloading tower. The bases are described below.

[0055] Figure 2 is a perspective view of the loading / unloading tower 5 of a tank according to an embodiment of the present invention.

[0056] 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 includes, near the rear wall 8, an upwardly protruding cuboid-shaped space (not shown), referred to as a liquid dome. The liquid dome is defined by a front transverse wall and a rear transverse wall and two side walls that extend vertically and protrude upward from the upper wall 9. The liquid dome also includes a horizontal cover 10 from which the loading / unloading tower 5 is suspended.

[0057] The loading / unloading tower 5 extends generally over the entire height of the tank. The loading / unloading tower 5 includes M masts, where M is an integer between 2 and 4 (including 2 and 4), here three masts 11, 12, 13. The three masts each extend along a vertical axis and are fixed to each other by crossbeams 15. In other words, the loading / unloading tower includes two, three, or four masts. When the tower 5 includes three masts, the term "tripod structure" is used. Each of the masts 11, 12, 13 is hollow and passes through the cover 10 of the liquid dome.

[0058] Advantageously, the masts 11, 12, 13 together with the crossbeams 15 define a triangular cross-section prism.

[0059] The tank for storing and / or transporting fluids according to the present invention further comprises support legs 14 fixed to the bottom wall of the tank. The storage and / or transport tank further comprises N discharge pumps 21, 22, 23, where N is an integer between 1 and 4 (inclusive of 1 and 4) and less than or equal to M. In other words, the tank comprises one, two, three or four unloading pumps, and the number of pumps is less than or equal to the number of masts. Finally, the tank comprises a base 200 located at the lower end of the loading / unloading tower 5 and connected to the support legs 14. Hereinafter, the present invention will be described in the case where N is equal to 3 (that is, in a tank comprising three unloading pumps, each associated with a mast) and M is equal to 3. The description of the present invention is exactly the same in the case where the tank comprises only one unloading pump or two unloading pumps. Similarly, the description of the present invention is exactly the same in the case where the tower comprises two masts or three masts or four masts. In the case of two (or one) unloading pumps and three masts, one (or two) masts are not associated with a pump. That mast (or those two masts) retains a structural role without changing the characteristics of the base described hereinafter. In the case where the tower comprises four masts, due to the description of the present invention, those skilled in the art will understand that the base described hereinafter can be the same as that described hereinafter (that is, having three guiding devices) or adapted to provide four guiding devices in a manner similar to that described hereinafter for three masts. Thus, the specification and the drawings show three pumps and three masts, but the present invention is not limited thereto.

[0060] According to the present invention, each of the three pumps 21, 22, 23 is provided at the lower end of the loading / unloading tower 5, and each of the three pumps 21, 22, 23 is in line with and fluidly connected to the masts 11, 12, 13. The physical and fluid connection between the pump and the mast is provided, for example, in a known manner by 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 (or two) masts are not associated with a pump, there is no flange on said mast.

[0061] In the embodiment described hereinafter, the pump is connected to the mast by a connecting member 500, so as to enable 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 the two ends opening towards the mast to which the connecting member is connected, and the other of the two ends opening towards the outlet opening of the pump. In other words, each end of the connecting member 500 cooperates with the pump or the mast respectively. The connecting member 500 enables a fluid connection between the pump and the mast.

[0062] Here, the two openings of the connecting member have different diameters. In these specific examples, the diameter of the opening of the connecting member 500 that mates with the pump is smaller than the diameter of the opening of the connecting member 500 that mates with the mast.

[0063] Embodiments not shown propose omitting this connecting member and replacing it with a gasket that can be adjusted to account for the height at which the pump is located. This configuration is possible especially when the outlet of the pump has the same diameter as the mast to which the pump is connected.

[0064] This arrangement enables not only reducing the weight of the loading / unloading tower, but also reducing the connection height that connects the upper part of the base to the mast, and thus reducing the influence of the sloshing effect associated with the movement of the liquid in the tank.

[0065] The base according to the invention comprises anchoring means fixed to three pumps and extending in a first horizontal plane (when there are at least two pumps, the anchoring means extends between two adjacent pumps), means for vertically guiding each pump relative to the base, and a first holding arm for each mast, the first holding arm extending from the anchoring means to the mast along a first axis intersecting the first horizontal plane. Details of this innovative base are described below.

[0066] Figure 3 is a perspective view of a first embodiment of the base 100 according to the invention. As Figure 3 can be seen, each of the three pumps 21, 22, 23 is provided at the lower end of the loading / unloading tower 5, each of the three pumps 21, 22, 23 is in line with and fluidly connected to the masts 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. Based on what has been explained above, those skilled in the art will understand that one or two pumps can be omitted without changing the core of the invention. Flange connectors connect the upper ends of the pumps to the lower ends of the masts. The three masts 11, 12, 13 and the crossbeam 15 project into the plane of the bottom wall to form a triangle, and the pumps 21, 22, 23 are provided at the respective vertices of the triangle.

[0067] By positioning each pump below the mast, the minimum required distance between the pumps is satisfied, and the position of the loading / unloading tower in the tank can be close to or far from the sidewall of the tank. The presence of three pumps in the tank enables achieving a greater unloading flow rate than that of the same tank with two pumps. Therefore, for a tank with a larger volume, the unloading time can be maintained the same as that of a traditional tank with a smaller volume. In addition, adding a third pump in the tank enables omitting the existing retractable emergency pump to mitigate the failure of one of the pumps.

[0068] According to the present invention, the base 100 includes anchoring means 110 which are fixed to three pumps 21, 22, 23 and extend between two adjacent pumps in a first horizontal plane P1. More precisely, each pump is equipped with fixing lugs 31 (preferably at least two fixing lugs), which are provided at the upper end of the pump. The anchoring means 110 are fixed to the pumps by the fixing lugs 31. Thus, the anchoring means 110 provide the connection of the paired pumps in the same plane P1 (here a direct connection). The anchoring means define the upper part of the base, and together with the lower part of the base which will be described in detail hereinafter, the anchoring means are capable of absorbing the forces caused by sloshing. Although the impact of the liquefied gas on the tower 5 due to sloshing causes hydrodynamic forces, such a configuration ensures the mechanical strength of the base.

[0069] The base includes vertical guiding means 111 for vertically guiding each pump with respect to the base 100. The vertical guiding means are capable of achieving the vertical relative movement between the pump and the base caused by the thermal contraction effect of contact with the liquefied gas. By associating the anchoring means 110 and the vertical guiding means 111, the base 100 prevents the horizontal movement of the pumps. Thus, the pumps and the masts of the tower do not have the degree of freedom of horizontal translational movement, so that all components are kept in place despite the sloshing impact. However, a degree of freedom of vertical translational movement is enabled between the pump and the base, so that the pump body, which is usually made of aluminum, can thermally contract with respect to the base, which is made of, for example, stainless steel.

[0070] Finally, the base 100 includes a first holding arm 112 for each mast, which extends from the anchoring means 110 to the mast along a first axis Z1 intersecting the first horizontal plane P1. The holding arm transfers the force from the mast to the base. As will be clearly visible hereinafter, the base is connected to the support structure by support legs 14, and the holding arm constitutes a force transmission path between the mast and the support structure.

[0071] Figure 4 is a perspective view of a first embodiment of the base according to the present invention. In this figure, only the base 100 is shown (that is, the masts, pumps, and support legs are not shown).

[0072] The anchoring means 110 includes at least one collar portion 113 and a skirt portion 114 for each pump, the at least one collar portion being fixed to the upper part of the pump, and the skirt portion extending from the at least one collar portion along an enclosing surface 115 at at least a first height h1 of the pump (this height is shown in Figure 3 ).

[0073] As Figure 3 shown, the collar portion 113 is fixed to the fixing lug 31 of the pump. In Figure 3 and Figure 4In the first embodiment shown, the skirt portion 114 extends vertically from the collar portion to the lower part of the pump. As described below, the skirt portion serves as a support for the vertical guiding means in addition to contributing to the mechanical strength of the base.

[0074] The base includes a fixed area 118 that extends in a second horizontal plane P2 different from the first horizontal plane P1 and connects the paired skirt portions of the three pumps. Advantageously, the second horizontal plane P2 is parallel to the first horizontal plane P1. The fixed area 118 defines the lower part of the base, and together with the upper part of the base, the fixed area 118 achieves good mechanical strength of the base in a restricted environment of liquefied gas transportation.

[0075] Advantageously, the base 100 further includes at least one structural connection member 119 between the fixed area 118 and the anchoring means 110. Although not shown, one or more other structural connection members 119 may connect the fixed area 118 and the anchoring means 110, for example, at an opening in the central part of the base. The structural connection member 119 stiffens between the upper and lower parts of the base to better distribute the forces applied at the first horizontal plane.

[0076] Figure 5 A pump guiding element of a first embodiment of the base according to the present invention is shown.

[0077] In this embodiment, each pump includes at least one first guiding element 116 provided at a first height h1 of the pump. The vertical guiding means includes a second guiding element 117 for each pump, which is fixed to the skirt portion 114 and has a shape complementary to that of the first guiding element 116. The second guiding element can move vertically in translation relative to the first guiding element.

[0078] More precisely, in this embodiment, the first guiding element 116 has two L-shaped ends 126. The second guiding element 117 includes two parallel flanges 127 that are spaced apart by the width of the first guiding element 116 between the two ends 126 of the first guiding element 116. The double L-shape formed by the two flanges 127 mates with the ends 126 of the guiding element 116. These complementary shapes provide freedom of vertical translational movement and block any horizontal translational movement.

[0079] Advantageously, each skirt portion 114 includes at least one lateral opening 140 facing the first guiding element 116, and advantageously, the second guiding element 117 has ends fixed to the corresponding opposite sides of the lateral opening 140. The opening 140 facilitates the installation and fixation of the second guiding element 117.

[0080] Figure 6 Shown is from a different angle fromFigure 5 The guiding element 117. In the installed position, the inner surface 128 is a surface having a shape complementary to that of the first guiding element 116. These inner surfaces may be provided with slide rails 129. The slide rails provide contact and relative movement between the first guiding element 116 and the second guiding element 117. The slide rails 129 may be made of HDPE (high density polyethylene).

[0081] Figure 7 is a detailed view seen from below the unloading tower, showing the guiding of the loading / unloading tower on the support legs.

[0082] 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 legs 14 have a circular cross-sectional shape in revolution and have a frustoconical lower part 54 which is connected to a cylindrical upper part at the smaller diameter end of the frustoconical lower part. The larger diameter bottom of the frustoconical part bears against the bottom wall of the support structure. The frustoconical lower part 54 generally extends through the thickness of the bottom wall of the tank, extending beyond the main sealing membrane. The cylindrical upper part is sealed by a circular plate. The main sealing membrane and the secondary sealing membrane are connected in a sealed manner to the frustoconical lower part 54.

[0083] The loading / unloading tower 5 includes guiding means fixed to the lower surface of the base 100, which cooperate with the 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 move in the height direction of the tank relative to the support legs 14 so that the loading / unloading tower 5 can contract or expand according to the temperature to which the loading / unloading tower is subjected, while preventing horizontal movement of the base 100 of the loading / unloading tower 5 by means of guiding elements 57, 59.

[0084] Thus, the base according to the invention is provided with an upper part (anchoring means) substantially in a plane P1 and a lower part (guiding means) substantially in a plane P2, the upper part and the lower part being connected to each other by a skirt and a 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.

[0085] Figure 8Perspective view of a second embodiment of the base according to the present invention. The base 200 includes the same elements as the base 100, namely: an anchoring device 120 fixed to 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 relative to the base 200, and a first holding arm 122 for each mast, the first holding arm extending from the anchoring device 120 to the mast along a first axis Z1 intersecting the first horizontal plane P1.

[0086] In this embodiment, the collar for each pump takes the form of a semi - circle and the collar surrounds the pump between two fixing lugs 31 that are radially opposite to the pump body with respect to the pump. The skirt portion 124 descends along the pump at a distance along the enclosing surface 125. The collar 123 and the skirt portion 124 form a housing half for the pump. The three housing halves are connected to the anchoring device extending in the horizontal plane P1 and the fixing area extending in the plane P2, thereby providing the stiffness of the base. Optionally, the base may include a structure ( Figure 8 not shown in the figure) between the fixing area 128 and the anchoring device 120 to strengthen the structure of the base and enable the transfer of forces from the upper part of the base to the lower part. In the same optional manner, the base may include a structure (not shown) between the fixing area and the skirt portion to strengthen the structure of the base and enable the transfer of forces from the upper part of the base to the lower part.

[0087] In the second embodiment, the anchoring device 120 is perforated in the first horizontal plane P1. Contrary to the anchoring device 110 that extends in material continuity in the plane P1 between the collars, the anchoring device 120 includes at least three main structures that extend in the plane P1 and connect pairs of collars 123. As Figure 8 shown, advantageously, the anchoring device 120 may include at least one additional structure for each pump that extends in the plane P1 between two main structures to strengthen the structure of the anchoring device. Thus, compared with the anchoring device 110, the anchoring device 120 contains less material, thereby reducing the weight on the ship.

[0088] Figure 9 Shows the guiding element of the pump of the second embodiment of the base according to the present invention.

[0089] The first guiding element 136 includes a collar 150 that is fixed around the pump at a first height h1. The collar 150 includes at least one projection 151 that extends radially towards the skirt portion 124 and a pin 152 that is disposed on the projection 151 and extends vertically. The second guiding element 137 includes two parts 153, 154 that are connected to each other. The two parts 153, 154 include a channel 155 that is provided with the pin 152. The channel 155 has a shape that is complementary to the pin 152. The part 153 is fixed to the skirt portion. The two parts 153, 154 may be made of HDPE. The two parts may be fixed to each other by arranging and clamping a plate 158 on the part 154 and the nut-bolt assembly 156, 157, as Figure 9 shown. Thus, the pin 152 fixed to the pump moves freely in translation in the channel 155 of the second guiding element 137 fixed to the base to achieve a vertical relative movement between the pump and the base due to thermal contraction.

[0090] It can be noted that the first guiding element 116 and the second guiding element 117 have been described with reference to the first embodiment, and the first guiding element 136 and the second guiding element 137 have been described with reference to the second embodiment. However, it is not beyond the scope of the present invention if the guiding elements 116, 117 are applied to the second embodiment and the guiding elements 136, 137 are applied to the first embodiment, which will be achievable by those skilled in the art after reading the description of the present invention.

[0091] Figure 10 is a perspective view of a third embodiment of the base according to the present invention. The base 300 includes the same elements as the base 200, namely: anchoring means 130 that are fixed to three pumps 21, 22, 23 and extend between two adjacent pumps in a first horizontal plane P1, vertical guiding means 131 for vertically guiding each pump relative to the base 300, and a first holding arm 132 for each mast that extends from the anchoring means 130 to the mast along a first axis Z1 that intersects the first horizontal plane P1.

[0092] In this embodiment, the collar 133 for each pump takes the form of a semi-circle and surrounds the pump between three fixed lugs 31 of the pump. The skirt portion 134 descends along the pump at a distance along the enclosing surface 135. The collar 133 and the skirt portion 134 form a housing portion for the pump. The three housing portions are connected to the anchoring means extending in the horizontal plane P1 and the fixed area extending in the plane P2, thereby generating the stiffness of the base. In the case where one (or two) pumps are omitted, the base remains exactly the same, and the collar 133 and the skirt portion 134 form a housing portion without a pump inside. Obviously, in this case, there is no flange and no fixed lug in the lower part of the mast. Optionally, the base may include a structure between the fixed area 138 and the anchoring means 130 (Figure 10 not shown) to reinforce the structure of the base and enable the transfer of forces from the top to the bottom of the base. Optionally, the base may also include a structure (not shown) between the fixed area and the skirt to reinforce the structure of the base and enable the transfer of forces from the upper part to the lower part of the base.

[0093] 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, compared to the anchoring device 110, the anchoring device 130 contains less material, which reduces the weight on the ship.

[0094] Figure 11 and Figure 12 is a perspective view of the fourth embodiment of the present invention. Note that in Figure 12 only the base 400 is shown (i.e., the mast, pump, and support legs are not shown).

[0095] The base 400 includes the same elements as the base 100, namely: an anchoring device 410 fixed to three pumps 21, 22, 23 (the third pump 23 is not visible in Figure 11 ).

[0096] The anchoring device 410 extends between two adjacent pumps in the first horizontal plane P1. The base 400 further includes vertical guiding devices 411 for vertically guiding each pump relative to the base 400, and at least one first holding arm 412 for each mast, the at least one first holding arm extending from the anchoring device 120 to the mast along a first axis Z1 intersecting the first horizontal plane P1.

[0097] The base includes a fixed area that extends in a second horizontal plane P2 different from the first horizontal plane P1 and connects the paired skirts of the three pumps here.

[0098] Here, the fixed area is perforated.

[0099] Advantageously, the second horizontal plane P2 is parallel to the first horizontal plane P1. The fixed area defines the lower part of the base 400, and together with the upper part of the base, it achieves good mechanical strength of the base in a restricted environment for transporting liquefied gas.

[0100] Thus, the base according to the present invention has an upper part (anchoring device 410) generally in the plane P1 and a lower part (guiding device 411) generally in the plane P2, and the upper and lower parts are connected to each other by the skirt 424 and structural connectors (if any).

[0101] The upper part of the base anchors the pumps and provides connection to the mast, while the lower part guides the pumps and the mast. This two-layer structure enables the arrangement of three pumps in the tank and meets the mechanical strength criteria required to withstand the forces applied to the loading / unloading tower and the equipment on this loading / unloading tower.

[0102] In this embodiment, the anchoring device 410 is perforated at the center of the anchoring device. Here, the anchoring device takes the form of a triangular opening, and the triangular opening has retaining arms for the mast at each vertex.

[0103] In this embodiment, the anchoring device 410 for each pump includes at least one collar portion 423 and a skirt portion 424 for each pump. The at least one collar portion is fixed to the upper part of the pump, and the skirt portion extends from the at least one collar portion to at least a first height of the pump on the enclosing surface 425.

[0104] The skirt portion 424 extends vertically from the collar portion 423 to the lower part of the pump. The skirt portion 424 is used to support the vertical guiding device in addition to contributing to the manual strength of the base 400.

[0105] In this embodiment, the collar portion 423 takes the form of a semi - circle, and the collar portion 423 surrounds the pump between two fixing lugs 431 that are radially opposite to the pump body with respect to the pump.

[0106] The skirt portion 424 descends along the pump at a distance along the enclosing surface 425. The collar portion 423 and the skirt portion 424 form a half - shell for the pump.

[0107] In this embodiment, the three half - shells surrounding each pump are connected to the anchoring device 410 extending in the horizontal plane P1 and the fixing area extending in the plane P2, thus generating the stiffness of the base 400.

[0108] The base optionally includes struts between the fixing area extending in the plane P2 and the anchoring device 410 to strengthen the structure of the base and enable the transfer of forces from the upper part of the base to the lower part.

[0109] Optionally, the base can also include struts (not shown) between the fixing area and the skirt portion to strengthen the structure of the base and enable the transfer of forces from the upper part of the base to the lower part. Thus, although the impact of liquefied gas on the tower 5 due to sloshing causes hydrodynamic forces, such a configuration enables the mechanical strength of the base to be ensured.

[0110] Here, the anchoring device 410 is perforated in the first horizontal plane P1 and includes at least three main struts that extend in the plane P1 and connect pairs of collars 413.

[0111] As Figure 11 and Figure 12 shown, advantageously, the base 400 includes at least one additional strut extending between two adjacent skirt portions 424. Here, the additional strut 600 extends in a plane parallel to plane P1, particularly in plane P2 of the fixed area.

[0112] For each embodiment of the present invention, the skirt portion may include a plurality of stiffeners 160, which preferably extend from the enclosing surface of the skirt portion in the vertical direction and / or the horizontal direction. These stiffeners strengthen the skirt portion.

[0113] In addition, the base may include second holding arms 212, 222, 232 for each mast, which extend from the anchoring device to the mast along a second axis Z2 that intersects the first horizontal plane P1 and is different from the first axis Z1. The second holding arms for each mast ensure a better distribution of the forces between the mast and the base.

[0114] As Figure 4 and Figure 12 shown, each holding arm may terminate in two rings 165 around the mast, where each holding arm is associated with the mast to hold the mast. Alternatively, each holding arm may terminate in a single ring 165. Alternatively, each holding arm may terminate in a holding cylinder designed to receive a portion of the mast.

[0115] In the case where the base includes two holding arms for each mast, one or more holding rings or cylinders are connected to the two holding arms.

[0116] Similarly, the base may also include lateral stiffeners 166 extending in the horizontal plane, where the two holding arms are associated with the mast. These lateral stiffeners 166 impart additional stiffness to the base at the holding arms.

[0117] Figure 13 is a schematic cross-sectional view of a tank according to the present invention for a ship 70 and a terminal for loading / unloading the tank. The cross-sectional view of the ship 70 shows a sealed and insulated tank 71 having a generally prismatic shape installed in the double hull 72 of the ship. The wall of the tank 71 includes a main sealing film intended to be in contact with the liquefied gas contained in the tank, a secondary sealing film arranged between the main sealing film and the double hull 72 of the ship, and two thermal insulation barriers respectively arranged between the main sealing film and the secondary sealing film and between the secondary sealing film and the double hull 72.

[0118] In a manner known per se, the loading / unloading pipeline 73 arranged on the top deck of the ship can be connected to a marine or port terminal through appropriate connectors to transfer the cargo of LNG from or to the tank 71.

[0119] Figure 13 An example of a marine terminal including a loading and / or unloading station 75, a subsea pipeline 76, and a land facility 77 is shown. The loading and unloading station 75 is a fixed offshore facility that includes a movable arm 74 and a tower 78 that supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can be connected to the loading / unloading pipeline 73. The directional movable arm 74 is suitable for ships of all sizes. Connecting pipes (not shown) extend inside the tower 78. The loading and unloading station 75 enables a ship 70 to load and unload from or to the land facility 77. The land facility 77 includes a liquefied gas storage tank 80 and a connecting pipe 81 that is connected to the loading or unloading station 75 via the subsea pipeline 76. The subsea pipeline 76 enables liquefied gas to be transferred over a relatively large distance (e.g., 5 km) between the loading or unloading station 75 and the land facility 77, which enables the ship 70 to maintain a relatively large distance from the shore during loading and unloading operations.

[0120] Pumps on the ship 70 and / or pumps equipped in the land facility 77 and / or pumps equipped in the loading and unloading station 75 are used to generate the pressure required to transfer the liquefied gas.

[0121] Although the present invention has been described in connection with multiple specific embodiments, it is obvious that the present invention is in no way limited to these embodiments, and if the device falls within the scope of the present invention, the present invention includes all technical equivalents and combinations of the described device.

[0122] The use of the verb “comprise” or “include” and its conjugate forms does not exclude the presence of elements or steps other than those recited in the claims.

[0123] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0124] It will be more generally obvious to those skilled in the art that various modifications can be made to the embodiments described above according to the teachings just disclosed. In the following claims, the terms used should not be construed as limiting the claims to the embodiments described in this specification, but should be construed to include all equivalents that the claims are intended to cover by their terms, which equivalents will be obvious to those skilled in the art based on their general background knowledge.

Claims

1. A tank for storing and / or transporting fluids for a ship, the tank comprising: · A loading / unloading tower (5), the loading / unloading tower comprising M masts (11, 12, 13), each mast extending along a vertical axis, M being an integer between 2 and 4 inclusive; · Support legs (14), the support legs being fixed to the bottom wall of the tank; · N unloading pumps (21, 22, 23), N being an integer between 1 and 4 inclusive and less than or equal to M; · A base (100, 200, 300), the base being located at the lower end of the loading / unloading tower (5) and connected to the support legs (14); The tank is characterized in that each of the N unloading pumps (21, 22, 23) is provided at the lower end of the loading / unloading tower (5), each of the N unloading pumps is in line with a mast (11, 12, 13) and is fluidly connected to the mast, And the base (100, 200, 300) comprises: · Anchoring means (110, 120, 130), the anchoring means being fixed to the N unloading pumps (21, 22, 23) and extending in a first horizontal plane (P1); · Vertical guiding means (111, 121, 131) for vertically guiding each pump relative to the base (100, 200, 300); · A first holding arm (112, 122, 132) for each mast, the first holding arm extending from the anchoring means (110, 120, 130) to the mast along a first axis (Z1) intersecting the first horizontal plane (P1).

2. The can according to claim 1, wherein, The anchoring means (110, 120, 130) comprises at least one collar portion (113, 123, 133) for each pump and a skirt portion (114, 124, 134), the at least one collar portion being fixed to the upper part of the pump, and the skirt portion extending from the at least one collar portion to at least a first height (h1) of the pump along an enclosing surface (115, 125, 135).

3. The can according to claim 2, wherein, Each pump comprises at least one first guiding element (116, 136) provided at the first height (h1) of the pump, wherein the vertical guiding means comprises a second guiding element (117, 137) for each pump, the second guiding element being fixed to the skirt portion and having a shape complementary to the first guiding element, and the second guiding element being capable of vertical translational movement relative to the first guiding element.

4. The can according to claim 2 or 3, wherein, The base comprises fixed areas (118, 128, 138) which extend in a second horizontal plane (P2) different from the first horizontal plane (P1) and connect the skirt portions of pairs of three pumps.

5. The can according to claim 4, wherein, The second horizontal plane (P2) is parallel to the first horizontal plane (P1).

6. The can according to claim 4 or 5, wherein The base (100, 200, 300) further includes at least one structural connection member (119, 129, 139) between the fixed area (118, 128, 138) and the anchoring device (110, 120, 130).

7. The can according to claim 3 in combination with any one of claims 2 to 5, wherein, Each skirt portion (114) includes at least one lateral opening (140) facing the at least one first guiding element (116), and the second guiding element (117) is fixed on the corresponding opposite side of the at least one lateral opening (140).

8. The can according to claim 3 in combination with any one of claims 2 to 5, wherein The at least one first guiding element (136) includes a collar (150) fixed around the pump at the first height (h1), the collar (150) includes at least one protrusion (151) radially extending towards the skirt portion (124) and a pin (152) provided on the at least one protrusion (151) and vertically extending, and the second guiding element (137) includes two parts (153, 154) connected to each other, and the two parts include a channel (155) provided with the pin (152).

9. The can according to any one of claims 2 to 8, wherein, At least one skirt portion (114, 124, 134) includes a plurality of strengthening members (160), and the strengthening members extend from the enclosing surface of the skirt portion, preferably extending from the enclosing surface of the skirt portion in the vertical direction and / or the horizontal direction.

10. The can according to any one of claims 1 to 9, wherein, The anchoring device (120, 130) is perforated in the first horizontal plane (P1).

11. The can according to any one of claims 1 to 10, wherein, The base includes a second holding arm (212, 222, 232) for each mast, and the second holding arm 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. A ship, the ship includes a hull forming a support structure and at least one tank according to any one of claims 1 to 11 anchored to the support structure.

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