Tank intended for ship for storing and / or transporting cargo of liquid gas

Abstract

To provide a loading / unloading tower comprising two to four masts and one to four unloading pumps disposed below the masts, the loading / unloading tower having an innovative base connected to lower ends of three masts.SOLUTION: A tank comprises a loading / unloading tower including M masts each extending along a vertical axis, N unloading pumps, and a base located at a lower end of the loading / unloading tower, where M is an integer from 2 to 4 inclusive and N is an integer from 1 to 4 inclusive and less than M. Each of the N unloading pumps is arranged at the lower end of the loading / unloading tower, aligned with a mast. The base comprises: an anchoring device fastened to the N unloading pumps and extending in a first horizontal plane; a device for vertically guiding each pump relative to the base; and, for each mast, a first support arm extending from the anchoring device to the mast along a first axis Z1 intersecting the first horizontal plane.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to the field of ships for transporting fluids such as, for example, liquefied natural gas (LNG). More specifically, the present invention relates to the field of tanks equipped on such ships for storing liquefied gas, such as natural gas in a liquid state. The tank is provided with a tower for loading / unloading liquefied natural gas, enabling the loading and / or unloading of the fluid into / from the tank.

Background Art

[0002] In the prior art, there is known a hermetically sealed thermal insulation tank for storing liquefied gas mounted on a ship, which has a loading / unloading tower. The loading / unloading tower is generally suspended from the ceiling wall of a support structure composed of the inner hull of the ship. Further, the tank has support legs 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 wavy primary seal film intended to come into contact with the liquefied gas. The wavy seal film has a plurality of wavy portions so as to have higher flexibility particularly when deformation associated with a large temperature change occurs.

[0004] Hereinafter, the background of the present invention and the present invention itself will be described by taking LNG as an example. However, the present invention is not limited thereto and can also be applied to other liquefied gases, liquefied petroleum gas, hydrogen, and ammonia, which are given as non-limiting examples.

[0005] Such an LNG carrier has traditionally had a total capacity of 174,000 m 3It includes four tanks for loading LNG. The loading / unloading tower of each tank is equipped with two unloading pumps. Each unloading pump is associated with a mast and can unload LNG by pumping the LNG through the mast. Each pump is generally offset with respect to the vertical axis along which the mast to which it is associated extends. More precisely, in the axial projection onto the bottom wall of the tank, each mast defines the outer perimeter. The fact that the pump is offset with respect to the vertical axis of the mast means that the pump is arranged completely outside the outer perimeter. The term "pump" refers to a combination consisting of an electric motor and a pump body configured to suck fluid, in this case the LNG present in the tank.

[0006] The time required for unloading from the ship is approximately 12 to 14 hours.

[0007] A new generation of ships can have three tanks for the same total loading capacity. Therefore, each tank has a larger capacity. However, it is desirable to maintain the same unloading time as that of ships with four tanks.

[0008] At sea, it is necessary to keep in mind that the sloshing phenomenon of the load occurs in the liquefied gas storage tank due to the action of the swell. This phenomenon tends to become very intense inside the tank, and as a result, large forces are generated inside the tank, especially on equipment such as the loading / unloading tower and pump fixing elements.

[0009] One idea that forms the background of the present invention is to add an additional discharge pump, i.e., a third discharge pump in the reference example, to increase the discharge flow rate in the tank. However, adding the third pump involves the difficulty of incorporating this additional pump into the tripod mast. In fact, in order for the pump to function properly, it is essential to comply with the distance between the pumps as defined by the pump supplier. Furthermore, depending on the ship, the position of the loading / unloading tower in the tank may be very close to the side wall of the tank or, on the contrary, at a large distance from this wall. Therefore, it must be possible to install three pumps while taking into account these layout constraints and the constraints regarding the sloshing phenomenon.

Summary of the Invention

[0010] The present invention aims to reduce some or all of the above problems by proposing a loading / unloading tower comprising from two to four masts (preferably three masts) and one, two, three, or four discharge pumps (the number of pumps being less than or equal to the number of masts), each arranged below a mast, and having an innovative base connecting to the lower ends of the three masts. The innovative base not only provides an interface between the masts, the pumps, and the support legs fixed to the bottom wall of the tank, but also allows vertical relative movement between the pumps and the base due to the effect of thermal contraction caused by contact with liquefied gas, while preventing horizontal movement of the pumps.

[0011] For this purpose, the present invention is directed to a tank intended for a ship for storing and / or transporting fluids, the tank comprising ● a loading / unloading tower comprising M masts each extending along a vertical axis, ● support legs fixed to the bottom wall of the tank, ● N discharge pumps, ● a base located at the lower end of the loading / unloading tower and connected to the support legs, and comprising where M is an integer from 2 to 4 and N is an integer from 1 to 4 and less than or equal to M.

[0012] According to the present invention, each of the N discharging pumps is arranged side by side on the mast at the lower end of the loading / unloading tower and is fluidly connected to the mast, The base ● An anchor device fixed to the N discharging pumps and extending in a first horizontal plane, ● A device for guiding each pump in the vertical direction with respect to the base, ● For each mast, a first holding arm extending from the anchor device to the mast along a first axis Z1 intersecting the first horizontal plane, is provided.

[0013] Advantageously, the anchor device includes, for each pump, at least one collar portion fixed to the upper part of the pump and a skirt extending from the at least one collar portion to at least a first height of the pump along an enclosing surface.

[0014] In the context of the present invention, "mast" means a substantially vertically hollow structural part as a whole in the loading / unloading tower extending from the bottom to the top of the storage tank.

[0015] Furthermore, the mast can support a platform (or the lid of the liquid dome) arranged at the upper part of the loading / unloading tower. Furthermore, the mast can have a diameter larger than the diameter of a pipe or duct for a fluid, for example, liquefied gas. Advantageously, each pump includes at least one first guide element arranged at the first height of the pump, and the vertical guide device includes, for each pump, a second guide element fixed to the skirt and having a shape complementary to the first guide element, and the second guide element is translatable vertically with respect to the first guide element.

[0016] Advantageously, the base is a fixed zone extending in a second horizontal plane different from the first horizontal plane, and includes a fixed zone connecting the skirt pairs of the three pumps.

[0017] Advantageously, the second horizontal plane is parallel to the first horizontal plane.

[0018] Advantageously, the base further includes at least one structural connection between the fixed zone and the anchor device.

[0019] In one embodiment of the present invention, each skirt includes at least one side opening facing the at least one first guide element, and the second guide element is fixed to each opposite side of the at least one side opening.

[0020] In another embodiment, the at least one first guide element includes a collar fixed around the pump at the first height, the collar including at least one convex portion extending radially towards the skirt and a pin disposed on the at least one convex portion and extending vertically, and the second guide element includes two portions connected to each other and including a portion having a channel in which the pin is disposed.

[0021] Advantageously, at least one skirt includes a plurality of reinforcing members extending preferably vertically and / or horizontally from the surrounding surface of the skirt.

[0022] Advantageously, the anchor device is perforated in the first horizontal plane.

[0023] Advantageously, the base includes, for each mast, a second holding arm extending from the anchor device to the mast along a second axis intersecting the first horizontal plane and different from the first axis.

[0024] Furthermore, the present invention relates to a ship including a hull forming a support structure and at least one such tank fixed to the support structure.

[0025] The above and other features and advantages of the present invention will become more apparent in light of the following description made with reference to the accompanying drawings as non-limiting examples.

Brief Description of the Drawings

[0026]

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DETAILED DESCRIPTION OF THE INVENTION

[0027] For clarity, the same reference numerals are given to the same elements in the various drawings.

[0028] The features, modifications, and embodiments of the present invention described above or described in the following detailed description can be associated with each other in various combinations, as long as they do not conflict with each other and are not mutually exclusive. In particular, a modification of the present invention that includes only the selection of features described below separately from other features of the description is envisioned if this selection of features is sufficient to provide a technical advantage and / or is sufficient to distinguish the present invention from the prior art.

[0029] The present invention relates to a closed thermally insulated tank for storing liquefied gas. The tank has a loading / unloading tower, enabling the loading of liquefied gas into the tank and / or the unloading from the tank. As a non-limiting example, the liquefied gas can be, in particular, liquefied natural gas (LNG).

[0030] Figure 1 is a schematic cutaway view of a closed thermally insulated tank according to the present invention for storing a fluid, having a loading / unloading tower.

[0031] A closed thermally insulated tank 1 for storing liquefied gas has a loading / unloading tower 5, enabling, in particular, the loading of liquefied gas into the tank 1 and / or the unloading therefrom. The liquefied gas can be, in particular, liquefied natural gas (LNG), i.e., a gas mixture mainly composed of methane and containing one or more other hydrocarbons such as ethane, propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, etc., and a small amount of nitrogen.

[0032] The tank 1 is fixed to a support structure 3 mounted on a ship. The support structure 3 is formed, for example, by the double hull of the ship, but more generally, it can take the form of any type of rigid partition having appropriate mechanical properties. The tank 1 can be intended to transport liquefied gas or to receive liquefied gas that functions as fuel for the propulsion of the ship.

[0033] In one embodiment, the tank 1 is a membrane tank. In such a tank 1, each wall includes, from the outside to the inside in the direction of the wall thickness, a secondary thermal insulation barrier 4 including a heat insulation element in contact with the support structure 3, a secondary seal film 2 fixed to the heat insulation element of the secondary thermal insulation barrier 4, a primary thermal insulation barrier 6 including a heat insulation element in contact with the secondary seal film 2, and a primary seal film 7 fixed to the heat insulation element of the primary thermal insulation barrier 6, the primary seal film 7 being intended to be in contact with the fluid contained in the tank 1.

[0034] In FIG. 1, the loading / unloading tower 5 is installed near the rear wall 8 of the tank 1. Thereby, when the ship uses ballast in a specific way and is tilted backward as a whole, the amount of load that can be unloaded by the loading / unloading tower 5 can be optimized.

[0035] The bases (100, 200, 300, 400) for fixing and guiding the pumps are located at the lower part of the loading / unloading tower. The bases will be described below.

[0036] FIG. 2 is a perspective view of the loading / unloading tower 5 of the tank according to an embodiment of the present invention.

[0037] 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, in the vicinity of the rear wall 8, a rectangular parallelepiped-shaped space, not shown, called a liquid dome, which protrudes upward. The liquid dome is defined by a front transverse wall, a rear transverse wall, and two side walls that extend vertically from the upper wall 9 and protrude upward. The liquid dome further includes a horizontal lid 10 from which the loading / unloading tower 5 is suspended.

[0038] The loading / unloading tower 5 extends substantially over the entire height of the tank. The loading / unloading tower 5 is provided with M masts. M is an integer of 2 or more and 4 or less. Here, three masts 11, 12, and 13 each extend along the vertical axis and are fixed to each other by cross members 15. In other words, the loading / unloading tower is provided with two, three, or four masts. When the tower 5 is provided with three masts, the term tripod structure is used. Each of the masts 11, 12, and 13 is hollow and passes through the lid 10 of the liquid dome.

[0039] The masts 11, 12, and 13 advantageously define, together with the cross member 15, a prism with a triangular cross section.

[0040] The tank for storing and / or transporting a fluid according to the present invention also includes support legs 14 fixed to the bottom wall of the tank. The storage and / or transport tank also includes N discharge pumps 21, 22, 23. N is an integer of 1 or more and 4 or less and M or less. In other words, the tank includes one, two, three, or four discharge pumps, and the number of pumps is less than or equal to the number of masts. Finally, the tank includes 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 the case of a tank having three discharge pumps each associated with a mast and M is equal to 3. The description of the present invention is exactly the same even when the tank has only one discharge pump or only two discharge pumps. Similarly, the description of the present invention is exactly the same even when the tower has two masts, three masts, or four masts. In the case of two (one each) discharge pumps and three masts, one (two each) mast is not associated with a pump. The mast (two masts each) continues to serve a structural role without changing the features of the base described below. In the present example where the tower has four masts, those skilled in the art will understand from the description of the present invention that the base described below may be the same as the following description (i.e., having three guide devices), or may be adapted to be provided with four guide devices in a manner similar to that described below for three masts. Therefore, although the present description and drawings describe three pumps and three masts, the present invention is not limited thereto.

[0041] According to the present invention, each of the three pumps 21, 22, and 23 is arranged side by side on the masts 11, 12, 13 at the lower end of the loading / unloading tower 5 and is fluidly connected to the masts. The physical and fluid connection between the pump and the mast is provided in a known manner, for example, by a flange adapted such that the diameter matches the outlet of the pump body and the outlet of the mast. If one (or two) of the masts is not associated with a pump, there is no flange on that mast.

[0042] In the embodiment described below, the pump is connected to the mast by a connection part 500 that enables a fluid connection between the outlet of the pump and the mast to which it is connected. In this embodiment, the connection part 500 is cylindrical and has two ends. One of the two ends opens facing the mast to which it is connected, and the other opens facing the outlet of the pump. In other words, each of the ends of the connection part 500 cooperates with either the pump or the mast respectively. The connection part 500 enables a fluid connection between the pump and the mast.

[0043] Here, the two openings of the connection part have different diameters. In these specific examples, the diameter of the opening of the connection part 500 that cooperates with the pump is smaller than the diameter of the opening of the connection part 500 that cooperates with the mast.

[0044] In an embodiment not shown, it is proposed to omit this connection part and substitute it with an adjustable shim in consideration of the height at which the pump is arranged. This form is possible especially when the outlet of the pump has the same diameter as the mast to which this pump is connected.

[0045] With such a configuration, not only can the weight of the loading / unloading tower be reduced, but also the height of the connection part connecting the upper part of the base to the mast can be lowered, so that the influence of sloshing that causes the movement of the liquid in the tank is reduced.

[0046] The base according to the present invention is fixed to three pumps and has an anchor device extending in a first horizontal plane (when there are at least two pumps, the anchor device extends between two adjacent pumps), a device for guiding each pump vertically with respect to the base, and for each mast, a first holding arm extending from the anchor device to the mast along a first axis intersecting the first horizontal plane. Details of this innovative base will be described below.

[0047] FIG. 3 is a perspective view of a first embodiment of a base 100 according to the present invention. As shown in FIG. 3, each of the three pumps 21, 22, 23 is arranged side by side on masts 11, 12, 13 at the lower end of the loading / unloading tower 5 and is fluidly connected to the masts. In other words, pump 21 is arranged below mast 11, pump 22 is arranged below mast 12, and pump 23 is arranged below mast 13. In light of the above description, those skilled in the art will understand that one or two pumps can be omitted without changing the essence of the present invention. A flange connection connects the upper end of the pump to the lower end of the mast. In the projection of the bottom wall onto a plane, the three masts 11, 12, 13 and the cross member 15 form a triangle, and the pumps 21, 22, 23 are arranged at the respective vertices of the triangle.

[0048] By arranging each pump below the mast, while complying with the minimum required distance between the pumps, the position of the loading / unloading tower can be brought closer to or further away from the side wall of the tank. The presence of three pumps in the tank can achieve a greater discharge flow rate than the discharge flow rate of an identical tank with two pumps. Therefore, for a large-capacity tank, the same discharge time as that of a conventional small-capacity tank can be maintained. Furthermore, by adding a third pump to the tank, the redundant emergency pump that is present to mitigate the failure of one of the pumps can be omitted.

[0049] According to the present invention, the base 100 is an anchor device 110 fixed to three pumps 21, 22, 23, and includes an anchor device 110 extending between two adjacent pumps in the first horizontal plane P1. More precisely, each pump has fixing protrusions 31 arranged at its upper end, preferably at least two fixing protrusions 31. The anchor device 110 is fixed to the pump by the fixing protrusions 31. Thus, the anchor device 110 forms a connection between the pumps that are paired in the same plane P1, here a direct connection. The anchor device can absorb the forces generated by sloshing while defining the upper part of the base and, together with the lower part of the base described in detail below. With such a configuration, even if hydrodynamic forces are generated by the liquefied gas colliding with the tower 5 due to sloshing, the mechanical strength of the base is guaranteed.

[0050] The base includes a device 111 for guiding each pump vertically with respect to the base 100. The vertical guiding device enables relative vertical movement between the pump and the base caused by the influence of thermal contraction due to contact with the liquefied gas. By associating the anchor device 110 with the vertical guiding device 111, the base 100 prevents horizontal movement of the pump. As a result, since the pump and the mast of the tower have no degree of freedom of horizontal translational movement, everything is held in place even under the impact of sloshing. However, since a degree of freedom of vertical translational movement between the pump and the base is allowed, thermal contraction of the pump body, which is generally made of aluminum, with respect to the base, which is made of, for example, stainless steel, is possible.

[0051] Finally, the base 100 includes a first holding arm 112 extending from the anchor device 110 to the mast along a first axis Z1 intersecting the first horizontal plane P1 for each mast. The holding arm transmits force from the mast to the base. As will become clear below, since the base is connected to the support structure by the support legs 14, the holding arm constitutes a force transmission path between the mast and the support structure.

[0052] Figure 4 is a perspective view of a first embodiment of a base according to the present invention. In this drawing, only the base 100 is shown (i.e., the mast, pump, and support legs are not shown).

[0053] The anchor device 110 includes, for each pump, at least one collar portion 113 fixed to the upper part of this pump, and a skirt 114 extending from at least one collar portion along the surrounding surface 115 over at least a first height h1 of the pump (this height is shown in FIG. 3).

[0054] As shown in FIG. 3, the collar portion 113 is fixed to the fixing projection 31 of the pump. In the first embodiment shown in FIGS. 3 and 4, the skirt 114 extends vertically from the collar portion to the lower part of the pump. As described below, the skirt not only contributes to the mechanical strength of the base but also functions as a support for the vertical guiding device.

[0055] The base has a fixing zone 118 extending in a second horizontal plane P2 different from the first horizontal plane P1, and includes a fixing zone 118 connecting the skirt pairs of the three pumps. The second horizontal plane P2 is preferably parallel to the first horizontal plane P1. The fixing zone 118 achieves good mechanical strength of the base in an environment with restrictions on liquefied gas transportation while defining the lower part of the base together with the upper part of the base.

[0056] The base 100 preferably further includes at least one structural connection portion 119 between the fixing zone 118 and the anchor device 110. Although not shown, one or more structural connection portions 119 can connect the fixing zone 118 and the anchor device 110, for example, at the level of the opening in the central part of the base. The structural connection portion 119 can better disperse the force applied at the level of the first horizontal plane in order to reinforce the base between the upper and lower parts.

[0057] Figure 5 shows the pump guide element of the first embodiment of the base according to the present invention.

[0058] In this embodiment, each pump includes at least one first guide element 116 disposed at a first height h1 of the pump. The vertical guide device includes, for each pump, a second guide element 117 fixed to the skirt 114, the second guide element 117 having a shape complementary to that of the first guide element 116. The second guide element is vertically translatable relative to the first guide element.

[0059] More precisely, in this embodiment, the first guide element 116 has two L-shaped ends 126. The second guide element 117 includes two parallel flanges 127 spaced apart by the width between the two ends 126 of the first guide element 116. The two L-shapes formed by the two flanges 127 cooperate with the ends 126 of the guide element 116. These complementary shapes provide freedom of movement in the vertical translation direction while preventing any horizontal translation movement.

[0060] Each skirt 114 preferably includes at least one lateral opening 140 facing the first guide element 116. The second guide element 117 preferably has its ends fixed to the respective opposing sides of the lateral opening 140. The opening 140 facilitates the installation and fixation of the second guide element 117.

[0061] FIG. 6 shows the guide element 117 of FIG. 5 viewed from different angles. At a predetermined position, the inner surface 128 is a surface having a shape complementary to that of the first guide element 116. Skids 129 may be provided on these inner surfaces. The skids provide contact and relative movement between the first guide element 116 and the second guide element 117. The skids 129 may be made of HDPE (high density polyethylene).

[0062] FIG. 7 is a detailed view from below the loading / unloading tower, showing the guide of the loading / unloading tower on the support legs.

[0063] Conventionally, the tank has support legs 14 fixed to the support structure in the area of the bottom wall of the tank. The support legs are adapted to guide the vertical translation of the loading / unloading tower. The support legs 14 have a rotating circular cross-sectional shape with a frustoconical lower part 54. The lower part 54 is connected to a cylindrical upper part at its small-diameter end. The large-diameter base of the frustoconical part abuts against the bottom wall of the support structure. The frustoconical lower part 54 typically penetrates the thickness of the bottom wall of the tank and extends beyond the level of the primary seal film. The cylindrical upper part is closed in a sealed manner by a circular plate. The primary seal film and the secondary seal film are connected to the frustoconical lower part 54 in a sealed manner.

[0064] The loading / unloading tower 5 includes a guiding device fixed to the lower surface of the base 100 and cooperating with the support legs 14 fixed to the bottom wall of the support structure. Such a guiding device is intended to allow the movement of the loading / unloading tower 5 relative to the support legs 14 in the height direction of the tank. Thereby, while the horizontal movement of the loading / unloading tower 5 is prevented by the guiding elements 57, 59, the loading / unloading tower 5 can contract or expand according to the temperature it receives.

[0065] Therefore, the base according to the present invention is essentially provided with an upper part (anchor device) in plane P1 and a lower part (guiding device) in plane P2, which are connected to each other by a skirt and a structural connection (if any). The upper part fixes the pump and serves as a connection part to the mast. On the other hand, the lower part guides the pump and the mast. With this two-stage structure, three pumps can be arranged in the tank, and the mechanical strength criteria required to support the forces applied to the loading / unloading tower and its equipment are satisfied.

[0066] FIG. 8 is a perspective view of a second embodiment of the base according to the present invention. The base 200 includes the same elements as the base 100. That is, an anchor device 120 fixed to three pumps 21, 22, 23, the anchor device 120 extending between two adjacent pumps in a first horizontal plane P1, a vertical guide device 121 for guiding each pump with respect to the base 200, and a first holding arm 122 extending from the anchor device 120 to the mast along a first axis Z1 intersecting the first horizontal plane P1 with respect to each mast.

[0067] In this embodiment, the collar for each pump takes a semi-circular shape and surrounds the pump between its two fixing protrusions 31 diametrically opposed to the pump body. The skirt 124 descends along the pump and is spaced apart along the deployment surface 125. The collar 123 and the skirt 124 form a half-shell for the pump. The three half-shells connect an anchor device extending in the horizontal plane P1 and a fixing zone extending in the plane P2, providing the rigidity of the base. The base may optionally comprise a structure (not shown in FIG. 8) between the fixing zone 128 and the anchor device 120 so as to reinforce the structure of the base and enable the transmission of force from the upper part to the lower part of the base. Similarly, in an alternative embodiment, the base may comprise a structure (not shown) between the fixing zone and the skirt so as to reinforce the structure of the base and enable the transmission of force from the upper part to the lower part of the base.

[0068] In the second embodiment, the anchor device 120 is perforated in the first horizontal plane P1. In contrast to the anchor device 110 where the material extends continuously between the collars in the plane P1, the anchor device 120 comprises at least three main structures extending in the plane P1, including a main structure connecting the paired collars 123. As shown in FIG. 8, the anchor device 120 may advantageously comprise, for each pump, at least one additional structure extending between two main structures in the plane P1 to reinforce the structure of the anchor device. Thus, since the anchor device 120 is composed of less material compared to the anchor device 110, the weight on the ship is reduced.

[0069] FIG. 9 shows the guide element of the pump according to the second embodiment of the base of the present invention.

[0070] The first guide element 136 comprises a collar 150 fixed around the pump at the first height h1. The collar 150 includes at least one protrusion 151 extending radially towards the skirt 124 and a pin 152 disposed on the protrusion 151 and extending in the vertical direction. The second guide element 137 comprises two parts 153, 154 connected to each other, including the part 153, 154 including a channel 155 in which the pin 152 is disposed. The channel 155 has a complementary shape to the pin 152. The part 153 is fixed to the skirt. These two parts 153, 154 may be composed of HDPE. As shown in FIG. 9, these two parts can be fixed to each other by placing a plate 158 on the part 154 and tightening with nut-bolt assemblies 156, 157. Thus, since the pin 152 fixed to the pump moves freely in translation in the channel 155 of the second guide element 137 fixed to the base, vertical relative movement between the pump and the base due to thermal contraction is made possible.

[0071] Note 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, applying the guide elements 116 and 117 to the second embodiment and applying the guide elements 136 and 137 to the second embodiment do not exceed the scope of the present invention. Those skilled in the art will be able to implement this upon reading the description of the present invention.

[0072] FIG. 10 is a perspective view of a third embodiment of a base according to the present invention. The base 300 includes the same elements as the base 200. That is, an anchor device 130 fixed to the three pumps 21, 22, and 23, the anchor device 130 extending between two adjacent pumps in the first horizontal plane P1, a device 131 for guiding each pump vertically with respect to the base 300, and a first holding arm 132 extending from the anchor device 130 to the mast along a first axis Z1 intersecting the first horizontal plane P1 with respect to each mast.

[0073] In the present embodiment, the color 133 for each of the pumps has a circular shape and surrounds the pump between its three fixing projections 31. The skirt 134 descends along the pump and is spaced apart along the surrounding surface 135. The color 133 and the skirt 134 form a shell portion for the pump. The three shell portions connect an anchor device extending in the horizontal plane P1 and a fixing zone extending in the plane P2, and the base is rigid. Even in the situation where there is one (or two) pump missing, the base remains exactly the same, and the color 133 and the skirt 134 form a shell portion without a pump inside. Of course, in such a situation, there is no flange at the lower part of the mast and no fixing projection either. The base may optionally include a structure (not shown in FIG. 10) between the fixing zone 138 and the anchor device 130 so as to reinforce the structure of the base and enable the transmission of force from the upper part to the lower part of the base. Also, the base may optionally include a structure (not shown) between the fixing zone and the skirt so as to reinforce the structure of the base and enable the transmission of force from the upper part to the lower part of the base.

[0074] In the third embodiment, similar to the second embodiment, the anchor device 130 is perforated in the first horizontal plane P1. Therefore, since the anchor device 130 is composed of less material compared to the anchor device 110, the weight on the ship is reduced.

[0075] FIGS. 11 and 12 are perspective views of the fourth embodiment of the present invention. It should be noted that in FIG. 12, only the base 400 is shown (that is, the mast, the pumps, and the support legs are not shown).

[0076] The base 400 includes the same elements as the base 100. That is, it includes an anchor device 410 fixed to the pumps 21, 22, 23 (the third pump 23 is not visible in FIG. 11).

[0077] The anchor device 410 extends between two adjacent pumps in the first horizontal plane P1. The base 400 further includes a device 411 for guiding each pump vertically with respect to the base 400, and at least one first holding arm 412 extending from the anchor device 120 of the mast along a first axis Z intersecting the first horizontal plane P1 with respect to each mast.

[0078] The base is a fixed zone extending in a second horizontal plane P2 different from the first horizontal plane P1, and here it includes a fixed zone connecting the skirt pairs of three pumps.

[0079] Here, the fixed zone is perforated.

[0080] The second horizontal plane P2 is preferably parallel to the first horizontal plane P1. The fixed zone, while defining the lower part of the base 400, together with the upper part of the base 400, achieves good mechanical strength of the base in an environment with constraints on liquefied gas transportation.

[0081] Thus, the base according to the present invention essentially has an upper part (anchor device 410) in plane P1 and a lower part (guide device 411) in plane P2, which are connected to each other by a skirt 424 and a structural connection (if any).

[0082] The upper part of the base fixes the pumps and serves as a connection part to the mast. On the other hand, the lower part guides the pumps and the mast. With this two - stage structure, three pumps can be arranged in the tank, and the mechanical strength criteria required to support the forces applied to the loading / unloading tower and its equipment are met.

[0083] In this embodiment, the anchor device 410 is perforated at its center. Here, the perforation takes the form of a triangular opening having holding arms for the mast at each vertex.

[0084] In this embodiment, the anchor device 410 for each pump includes, for each pump, at least one collar portion 423 fixed to the upper part of the pump, and a skirt 424 extending from at least one collar portion 423 to at least a first height of the pump on the surrounding surface 425.

[0085] The skirt 424 extends vertically from the collar portion 423 to the lower part of the pump. The skirt 424 not only contributes to the manual strength of the base 400 but also functions to support the vertical guiding device.

[0086] In this embodiment, the collar portion 423 has a semi-circular shape and surrounds the pump between its two fixing protrusions 431 facing each other in the diametrical direction with respect to the pump body.

[0087] The skirt 424 descends along the pump and is spaced along the surrounding surface 425. The collar portion 423 and the skirt 424 form a half-shell for the pump.

[0088] In this embodiment, three half-shells surrounding each pump connect an anchor device 410 extending in the horizontal plane P1 and a fixing zone extending in the plane P2, and the base 400 is rigid.

[0089] To strengthen the structure of the base and enable the transmission of force from the upper part to the lower part of the base, the base selectively includes a support column (not shown) between the fixing zone extending in the plane P2 and the anchor device 410.

[0090] Also, to strengthen the structure of the base and enable the transmission of force from the upper part to the lower part of the base, the base may selectively include a support column (not shown) between the fixing zone and the skirt. Thus, with such a structure, even if hydrodynamic forces are generated by the liquefied gas colliding with the tower 5 due to sloshing, the mechanical strength of the base is guaranteed.

[0091] Here, the anchor device 410 is perforated in the first horizontal plane P1 and includes at least three main struts extending in the plane P1, the main struts connecting paired collars 413.

[0092] As shown in FIGS. 11 and 12, the base 400 preferably includes at least one additional strut extending between two adjacent skirts 424. Here, this additional strut 600 extends in a plane parallel to the plane P1, particularly in the plane P2 of the fixed zone.

[0093] For each embodiment of the present invention, the skirt may preferably include a plurality of reinforcing members 160 extending from the surrounding surface of the skirt in the vertical and / or horizontal directions. These reinforcing members reinforce the skirt.

[0094] Furthermore, the base may include, for each mast, a second axis Z2 intersecting the first horizontal plane P1, and second holding arms 212, 222, 232 extending from the anchor device to the mast along a second axis Z2 different from the first axis Z1. By the second holding arms for each mast, it is ensured that the force is more favorably distributed between the mast and the base.

[0095] As shown in FIGS. 4 and 12, each holding arm may terminate at two rings 165 for surrounding and holding the mast to which it is associated. Alternatively, each holding arm may terminate at a single ring 165. Alternatively, each holding arm may terminate at a holding cylinder intended to receive a part of the mast.

[0096] When the base includes two holding arms for each mast, the holding ring or the holding cylinder connects the two holding arms.

[0097] Similarly, the base may also include a lateral reinforcing member 166 extending in a horizontal plane with the two holding arms associated with the mast. These lateral reinforcing members 166 provide additional rigidity to the base at the level of the holding arms.

[0098] FIG. 13 is a schematic cutaway view of a tank according to the present invention of a ship 70 and a terminal for loading / unloading the tank. The cutaway view of the ship 70 shows a generally prismatic, sealed and insulated tank 71 mounted on the double hull 72 of the ship. The wall of the tank 71 includes a primary seal film intended to contact the liquefied gas contained in the tank, a secondary seal film disposed between the primary seal film and the double hull 72 of the ship, and two insulation barriers respectively disposed between the primary seal film and the secondary seal film and between the secondary seal film and the double hull 72.

[0099] In a manner known per se, a loading / unloading pipe 73 arranged on the top deck of the ship is connected to an offshore terminal or a port terminal by suitable connectors so that the LNG load can be transferred from or to the tank 71.

[0100] FIG. 13 shows an example of an offshore terminal including a loading and / or unloading station 75, a subsea pipe 76, and onshore facilities 77. The loading and unloading station 75 is a fixed offshore facility including a movable arm 74 and a tower 78 supporting the movable arm 74. The movable arm 74 supports a bundle of heat-insulated flexible tubes 79 that can be connected to the loading / unloading pipe 73. The orientation-adjustable movable arm 74 is adaptable to ships of any size. A connecting pipe (not shown) extends inside the tower 78. The loading and unloading station 75 enables loading and unloading of the cargo of the ship 70 from and to the onshore facilities 77. The onshore facilities 77 include a liquefied gas storage tank 80 and a connecting pipe 81 that connects to the loading and unloading station 75 via the subsea pipe 76. The subsea pipe 76 enables transfer of liquefied gas between the loading or unloading station 75 and the onshore facilities 77 over a long distance, e.g., 5 km. Thereby, the ship 70 can stay at a long distance from the coast during the loading and unloading operations.

[0101] Pumps mounted on the ship 70 and / or pumps installed in the onshore facilities 77 and / or pumps installed in the loading and unloading station 75 are used to generate the pressure necessary to transfer the liquefied gas.

[0102] Although the present invention has been described with respect to a plurality of specific embodiments, it is understood that the present invention is not limited thereto, and that the present invention encompasses all technical equivalents and combinations of the means described, provided that they fall within the scope of the invention.

[0103] The use of the verb “include” or “comprise” and its conjugations does not exclude the presence of elements or steps other than those recited in the claims.

[0104] In the claims, reference signs in parentheses shall not be construed as limiting the claims.

[0105] In light of the disclosed teachings, it will be more clearly understood by those skilled in the art that various changes can be made to the above-described embodiments. The terms used in the following claims should not be construed as limiting the claims to the embodiments described herein, but should be construed to cover what is intended by the language of the claims and to include all equivalents that would be apparent to those skilled in the art based on general background knowledge.

Claims

1. A tank intended for a ship for storing and / or transporting a fluid, the tank comprising: ● A loading / unloading tower (5) having M masts (11, 12, 13) each extending along a vertical axis; ● Support legs (14) fixed to the bottom wall of the tank; ● N unloading pumps (21, 22, 23); ● A base (100, 200, 300) located at the lower end of the loading / unloading tower (5) and connected to the support legs (14); comprising In a tank where M is an integer of 2 or more and 4 or less, and N is an integer of 1 or more and 4 or less and M or less, Each of the N unloading pumps (21, 22, 23) is arranged side by side on the masts (11, 12, 13) at the lower end of the loading / unloading tower (5) and is fluidly connected to the masts. The base (100, 200, 300) ● Anchor devices (110, 120, 130) fixed to the N unloading pumps and extending in a first horizontal plane (P1); ● Devices (111, 121, 131) for guiding each pump vertically with respect to the base (100, 200, 300); ● First holding arms (112, 122, 132) extending from the anchor devices (110, 120, 130) to the masts along a first axis Z1 intersecting the first horizontal plane (P1) for each mast; comprising A tank characterized by the above.

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

3. Each pump comprises at least one first guide element (116, 136) arranged at the first height (h1) of the pump. The vertical guide device comprises, for each pump, a second guide element (117, 137) fixed to the skirt and having a shape complementary to that of the first guide element. The second guide element is vertically translatable with respect to the first guide element. The tank according to Claim 2.

4. The base is a fixed zone (118, 128, 138) extending in a second horizontal plane (P2) different from the first horizontal plane (P1), and includes a fixed zone (118, 128, 138) connecting the skirt pairs of the three pumps. The tank according to claim 2 or 3.

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

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

7. Each skirt (114) includes at least one side opening (140) facing the at least one first guide element (116). The second guide element (117) is fixed to respective opposite sides of the at least one side opening (140). The tank according to any one of claims 2 to 5 in combination with claim 3.

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

9. At least one skirt (114, 124, 134) includes a plurality of reinforcing members (160) extending preferably vertically and / or horizontally from the surrounding surface of the skirt. The tank according to any one of claims 2 to 8.

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

11. The base includes, for each mast, a second holding arm (212, 222, 232) that extends from the anchor 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 tank according to any one of claims 1 to 10. Claim 12 A ship including a hull forming a support structure and at least one tank according to any one of claims 1 to 11 fixed to the support structure.

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