CN109630879B

CN109630879B - Method for installing an anchoring device for a sealed and insulated tank

Info

Publication number: CN109630879B
Application number: CN201811109983.7A
Authority: CN
Inventors: C·舒鲁佩
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2017-09-29
Filing date: 2018-09-21
Publication date: 2020-02-07
Anticipated expiration: 2038-09-21
Also published as: JP6480073B1; CN109630879A; JP2019066042A; KR101855628B1; RU2694068C1

Abstract

The invention relates to a method of installing an anchoring device for a sealed and thermally insulated storage tank for storing a fluid, the storage tank comprising a first and a second load-bearing wall joined at the edges, the anchoring device comprising a connecting beam of flat metal sheets welded together to form: a hollow central core having a parallelogram cross-section, the central core having a first corner having the same value as the angle between the first and second load bearing walls; two secondary anchoring flanges protruding from the first corner towards the outside of the central core; two secondary connecting flanges projecting toward the outside of the central core in the opposite direction to the secondary anchoring flanges; two primary connecting flanges projecting from a second corner of the central core toward an outer side of the central core; and two primary anchor flanges projecting toward the outside of the central core in the direction opposite to the primary connecting flanges.

Description

Method for installing an anchoring device for a sealed and insulated tank

Technical Field

The present invention relates to the field of sealed and insulated storage tanks for storing and/or transporting fluids, such as cryogenic fluids.

The sealed and thermally insulated storage tank is mainly used for storing Liquefied Natural Gas (LNG), which is stored at atmospheric pressure at temperatures around-162 ℃.

Background

Tanks for LNG carrier vessels are known, for example, from french patent FR- A-2549575. The LNG carrying tank has a plurality of longitudinal tank walls and a plurality of transverse tank walls. Each wall of the tank has a double sealing membrane, which is inserted with a double insulating barrier. The tank is integrated into a load-bearing structure, which in this case is formed by the hull of the LNG carrier vessel.

The temperature change and the process of filling the storage tank can impose high stresses on the membrane of the storage tank when loading and unloading LNG. Similarly, during sea transport, the movement of the vessel may exert considerable forces on the barriers of the tank. In order to avoid degradation of the sealing and insulating properties of the tank, the primary and secondary sealing diaphragms are anchored to the load-bearing structure by means of connection rings at the corners between the transverse and longitudinal walls of the tank.

The anchoring of the connection rings on the load-bearing structure on the one hand and their connection to the sealing diaphragm on the other hand allows the transfer of loads between the diaphragm and the hull of the vessel, thus reinforcing the overall structure of the tank.

The coupling ring makes it possible in particular to withstand the tensile stresses induced by the thermal shrinkage of the metal elements forming the sealing barrier, the deformation of the hull in the sea and the process of filling the tank.

In FR- A-2629897 it has been proposed to prepare the coupling rings from beams having A square cross-section, which makes it possible to reduce the assembly operations on the ship.

When using such beams, the mounting operation must be carefully carried out, due to the high requirements for alignment: the offset between several successive beams may cause a lack of uniformity of the support surface intended to support the sealing membrane and therefore may cause a risk of local weakening of the membrane.

Disclosure of Invention

The invention is based on the idea of providing a method of mounting a wall of a tank in the vicinity of a joint between two walls forming an edge, which method offers advantages in terms of both precision and simplicity of operation.

The present invention provides a method of installing an anchoring device for a sealed and insulated tank for storing a fluid, and a sealed and insulated tank obtainable by the installation method.

The sealed and insulated tank comprises a plurality of tank walls, wherein each tank wall comprises in the thickness direction a load-bearing wall, a secondary insulating barrier anchored to the load-bearing wall, a secondary sealing membrane parallel to the load-bearing wall, a primary insulating barrier and a primary sealing membrane parallel to the load-bearing wall and designed to be in contact with the fluid in the tank.

The sealed and insulated storage tank mainly comprises:

-a load-bearing structure comprising a first load-bearing wall and a second load-bearing wall meeting at an edge, each of the first and second load-bearing walls having a primary anchoring plate and a secondary anchoring plate, the primary and secondary anchoring plates protruding towards the inside of the tank and being placed parallel to the edge, such that the distance between the secondary anchoring plate and the edge corresponds to the thickness of the secondary thermal barrier and the distance between the primary and secondary anchoring plates corresponds to the thickness of the primary thermal barrier, and

-a connecting beam consisting of flat metal sheets welded together to form:

a hollow central core having a parallelogram cross-section, the central core having a first corner having the same value as the angle between the first and second load-bearing walls, a first side having a length equal to the distance between the primary and secondary anchor plates of the first load-bearing wall, and a second side having a length equal to the distance between the primary and secondary anchor plates of the second load-bearing wall,

two secondary anchoring flanges projecting from a first corner of the central core towards the outside of the central core and aligned with two sides of the central core that meet at said first corner,

two secondary connecting flanges projecting towards the outside of the central core in a direction opposite to the secondary anchoring flanges with respect to the central core and also aligned with two sides of the central core that intersect at said first corner,

two primary connecting flanges projecting from a second corner of the central core, diagonally opposite to the first corner of the central core, towards the outside of the central core, and aligned with two side portions of the central core that intersect at said second corner, and

two primary anchoring flanges projecting towards the outside of the central core in a direction opposite to the primary connecting flanges with respect to the central core and also aligned with the two sides of the central core that meet at said second corner.

The invention also provides a connection beam, one or more insulating elements being fixed to and/or in the connection beam; the insulating elements may be selected from the group consisting of central insulating elements, side insulating elements, and corner insulating elements.

According to an embodiment, the insulating element is in the form of a parallelepiped chamber filled with insulating lining made of various materials, or in the form of a sandwich structure made of plywood-polyurethane foam-plywood.

According to one embodiment, the process starts with providing a load bearing structure and a connection beam, or using an already provided load bearing structure and connection beam, and further comprises the steps of:

attaching the connection beam parallel to the edges to the load-bearing structure by adjusting two secondary anchoring flanges in the direction of the secondary anchoring plates of the first and second load-bearing walls by means of a plurality of length-adjustable fasteners, which are placed between the two primary anchoring flanges and the primary anchoring plates of the first and second load-bearing walls,

adjusting the length of the length-adjustable fastener to adjust the distance and parallelism of the primary or secondary connecting flange relative to the reference surface,

welding two secondary anchoring flanges to the secondary anchoring plate of the first load-bearing wall and to the secondary anchoring plate of the second load-bearing wall, to secure the connecting beam to the load-bearing structure,

removing fasteners of adjustable length, an

The two primary anchoring flanges are fixed to the primary anchoring plates of the first bearing wall and the primary anchoring plates of the second bearing wall by welding the connecting plates together.

Due to these properties, the connection beams can be positioned precisely with respect to a reference surface provided by, for example, the load bearing structure, so that the connection beams of different sections can be aligned with a high degree of precision, i.e. typically with a deviation between two successive sections of less than +/-2 mm.

According to an embodiment, such an installation method may comprise the step of fixing one or more insulating elements to and/or in the connecting beam before attaching the connecting beam to the load-bearing structure; the insulating elements may be selected from the group consisting of central insulating elements, side insulating elements, and corner insulating elements.

According to one embodiment, the connecting beam is made of

Sheet or any other metal with a low coefficient of expansion.

According to one embodiment the load bearing structure of the first wall is a longitudinal wall of the vessel and the load bearing structure of the second wall is a transverse wall of the vessel.

According to one embodiment, the invention also provides a tank obtained by the installation method described above.

Such storage tanks may be part of an onshore storage facility, for example for storing LNG, or may be installed in floating, coastal or deep water structures, especially ethane or LNG carrier vessels, Floating Storage and Regasification Units (FSRU), floating production storage and offloading units (FPSO), etc. In the case of a floating structure, the storage tank may be designed to contain liquefied natural gas as fuel for propelling the floating structure.

According to one embodiment, a vessel for transporting fluids comprises a hull, such as a double hull, and the aforementioned tanks mounted in the hull.

The invention also provides, according to one embodiment, a method of loading or unloading such a vessel, wherein fluid is transferred back and forth between the vessel's tanks and a floating or onshore storage facility through insulated pipes.

According to one embodiment the invention also provides a transfer system for fluids, wherein the system comprises a vessel as described above, an insulated pipe arranged to connect a tank mounted in the hull of the vessel to a floating or onshore storage facility, and a pump for carrying fluids back and forth between the tank of the vessel and the floating or onshore storage facility through the insulated pipe.

Drawings

The invention will be better understood and other objects, details, features and advantages thereof will become more apparent in the course of the following description of several particular embodiments thereof, given for the purpose of illustration only and not for the purpose of exhaustive explanation, with reference to the accompanying drawings.

Figure 1 is a partially cut-away perspective view of a sealed and insulated tank at the junction between two walls.

Figure 2 is a cross-sectional view of the joint between two walls of the sealed and insulated tank shown in figure 1, when the connecting beams are positioned.

Figure 3 is an enlarged detailed view of the length-adjustable fastener used in positioning the connecting beam.

Figure 4 is a perspective view of the joint between two walls of the tank sealed and insulated during positioning of the connecting beams.

Fig. 5 is a perspective view of a connection beam according to a second embodiment.

Fig. 6 is a perspective view of a connection beam according to a third embodiment.

Figure 7 is a cut-away schematic illustration of a tank of an LNG carrier vessel and a quay for loading/unloading the tank.

Figure 8 is a schematic perspective view of a vessel comprising a plurality of tanks.

Detailed Description

Fig. 8 shows a vessel 70, such as an LNG carrier vessel, comprising a plurality of storage tanks 71.

Such a vessel 70 comprises a hull 90 formed with a load-bearing structure (shown in dashed lines in fig. 8) for a plurality of tanks 71 (shown in solid lines in fig. 8).

The tank 71 integrated in the hull 90 has a polyhedral shape. More specifically, the tank 71 has a bottom longitudinal wall 1a, a top longitudinal wall 1b, two longitudinal side walls 1c and lower and upper chamfered longitudinal walls 1 d.

The general construction of such a tank 71 is well known. Thus, considering that all walls of the tank may have a similar overall structure, only one wall region of the tank will be described.

With respect to fig. 1, a multi-layer structure of a tank wall 1 according to an embodiment is described. The tank wall 1 has, in the thickness direction of the tank, from the outside to the inside, a secondary thermal insulation barrier 6, a secondary sealing membrane 7, a primary thermal insulation barrier 8 and a primary sealing membrane 9 designed to be in contact with the fluid stored in the tank, wherein the secondary thermal insulation barrier 6 rests against the carrier wall 5.

Both the primary insulating barrier 8 and the secondary insulating barrier 6 are constituted by insulating elements, more particularly by parallelepiped insulating chambers 10, said insulating chambers 10 being juxtaposed in a regular pattern. Different techniques for making such insulating elements are known. For example, each of the heat insulation chambers 10 has a bottom plate 11 and a cover plate 12. The side plates 13 and the internal partition 14 extend between the bottom plate 11 and the lid plate 12 in the thickness direction of the tank wall. The side panels 13, the bottom panel 11 and the cover panel 12 and the inner partition 14 delimit a space in which an insulating lining, for example made of glass wool, polymer foam, expanded perlite or other material, is fitted. Each insulating chamber 10 is placed on the load-bearing wall 5 by means of anchoring means, which can be made in different ways according to known techniques and as described, for example, in the FR2973098 publication. The heat-insulating chambers 10 of the primary and secondary heat-insulating barriers 8 and 6 have primary and secondary membranes 9 and 7, respectively.

The secondary diaphragms 7 and the primary diaphragms 9 are for example constituted by a series of metal plates with folded edges, called parallel strips 15, these parallel strips 15 being alternated with elongated welded supports 16. The lath 15 and the welding support 16 are made of an alloy having a low coefficient of expansion. The laths 15 and the welding supports 16 are formed, for example, by

I.e. an alloy of iron and nickel, with a coefficient of expansion generally between 1.2 x 10^-6from/K to 2X 10^-6between/K or made of an iron alloy with a high manganese content, with a typical expansion coefficient of 7X 10^-6The order of/K. The thickness of the secondary membrane 7 and the primary membrane 9 is generally between 0.5mm and 1.5mm, preferably 0.7 mm.

The slats 15 comprise over the entire width a flat central strip and folded side edges, wherein the flat central strip rests against the cover plate 12 of the insulating chamber 10. The folded edges extend slightly perpendicular to the straight central strip. The folded edges of the strip 15 are hermetically welded to the welding support 16. The welding supports 16 are always placed at the lower thermal insulation barriers 6, 8, for example by being housed in inverted T or J form in a recess formed in the cover plate 12 of the thermal insulation chamber 10. More details of manufacturing such a membrane are given in the FR2968284 publication.

The following paragraphs more clearly describe the corner regions of the tank. Fig. 1 is a perspective view of a joint region 100 between a first tank wall 1 (extending in the yz plane) and a second tank wall 2 (extending in the xz plane).

At the joint 100, the carrier wall 5 of the first wall 1 and the carrier wall 25 of the second wall 2 meet at an edge 101 (extending in the z-direction), the secondary membranes 7, 27 and the primary membranes 9, 29 of the two tank walls 1, 2 being connected by anchoring means to anchor the secondary sealing membranes 7, 27 and the primary sealing membranes 9, 29 to the carrier wall 5 of the first wall 1 in a first aspect and to anchor the secondary sealing membranes 7, 27 and the primary sealing membranes 9, 29 to the carrier wall 25 of the second wall 2 in a second aspect.

More specifically, the secondary diaphragm 7 and the primary diaphragm 9 of the first wall 1 are anchored perpendicularly to the bearing wall 25 of the second wall 2. Similarly, the secondary diaphragm 27 and the primary diaphragm 29 of the second wall 2 are anchored perpendicularly to the bearing wall 5 of the first wall 1.

The anchoring means make it possible to withstand the tensile stresses caused by the thermal shrinkage of the secondary membranes 7, 27 and of the primary membranes 9, 29. The anchoring device also makes it possible to withstand the stresses caused by the deformation of the hull, in particular by the bending of the longitudinal walls of the vessel, which stresses correspond to the vessel beam effect.

The anchoring means comprise an elongated connecting beam 17, which connecting beam 17 has a hollow central core with a parallelogram cross-section, which in this case is rectangular, since the two bearing walls 5, 25 form a right angle. As with the sealing membrane, the connecting beam 17 may be made mainly of an alloy with a low coefficient of expansion, for example in sheet material with a thickness between 0.5mm and 1.5 mm.

In order to hold the connecting beam 17 on each side of the edge 101, each of the load bearing walls 5, 25 comprises a primary anchoring plate 30 and a secondary anchoring plate 31. The distance from the secondary anchor plate 31 to the edge 101 corresponds to the thickness of the secondary thermal barrier. The distance between anchorage plate 30 and anchorage plate 31 corresponds to the thickness of the primary thermal insulation barrier. The primary and

secondary anchor plates

30, 31 are for example between 6 and 12mm thick, preferably 8mm thick.

With reference to fig. 2 to 4, the following paragraphs will now describe more clearly the method of installing the above-described anchoring device.

As shown in fig. 2 and 4, the connecting beam 17 is made of flat metal sheets welded together to form:

a hollow central core 32 with a rectangular or square cross-section, the sides of the central core 32 parallel to the respective load-bearing walls having a length respectively equal to the distance between the primary anchoring plate 30 and the secondary anchoring plate 31 of the respective load-bearing wall,

two secondary anchoring flanges 33 projecting from a corner 34 of the central core towards the outside of the central core 32 and aligned with two sides 48 of the central core that meet at this corner 34,

two secondary connecting flanges 35 projecting towards the outside of the central core 32 in the opposite direction to the secondary anchoring flanges 33,

two primary connecting flanges 36 projecting from diagonally opposite corners 37 of the central core 32 towards the outside of the central core 32 and aligned with the two sides of the central core that meet at the corners 37,

two primary anchoring flanges 38 project towards the outside of the central core 32, in the opposite direction to the primary connecting flanges 36.

In the embodiment of fig. 2 and 3, the connecting beam 17 is a bare beam when being fixed to the load bearing structure. Alternatively, the connecting beam may be pre-assembled with one or more insulating elements before being fixed to the load-bearing structure.

Thus, fig. 5 illustrates a connecting beam 117, which differs from the connecting beam 17 in that, prior to attaching the connecting beam 117 to the load bearing structure:

the central insulating element 40 has been fixed in the central core 32 and/or

The side insulating elements 41 have been placed outside the central core 32 along the two sides 48 of the central core that meet at the corners 34.

The lateral insulating elements 41 fill two spaces located respectively along each of the two sides of the central core between the secondary anchoring flange 33 and the primary anchoring flange 38, and the lateral insulating elements 41 are fixed to the primary anchoring flange 38 and to the secondary anchoring flange 33.

Fig. 6 illustrates a connecting beam 217, which differs from the connecting beam 17 in that, prior to attaching the connecting beam 117 to the load bearing structure:

the central insulating element 40 has been fixed in the central core 32 and/or

Corner insulating elements 42 have been placed outside the central core 32 along the corners 34 between the two secondary anchoring flanges 33, and the corner insulating elements 42 are fixed to the two secondary anchoring flanges 33.

The insulating

elements

40, 41, 42 can be manufactured in different ways. Ideally, they are in the form of parallelepiped chambers, mainly made of plywood assembled together according to known techniques, filled with insulating lining, which may be made of different materials, such as glass wool, expanded perlite, expanded polystyrene or polymer foam. Alternatively, a plywood-polyurethane foam-plywood sandwich structure may be used as the insulating element.

Alternatively, the connecting beams may combine the preassembled insulating elements of fig. 5 and 6.

Returning to fig. 2, the first step before attaching the connecting

beams

17, 117, 217 to the load-bearing structure involves placing the first row of insulating elements 45 in the parallelepiped space between the end portions 46 of the first and second load-bearing walls 5, 25 and between the secondary anchoring plate 31 and the edge 101.

If a connecting beam 217 preassembled with corner insulating elements 42 is used, the first row of insulating elements 45 is formed with a recess 44, the outline of which recess 44 is shown in dashed lines in fig. 2, to accommodate the corner insulating elements 42 when the beam 217 is attached to the load-bearing structure parallel to the edge 101. If the above-mentioned connecting beams 217 are not used, the first row of insulating elements 45 preferably fills substantially the entire above-mentioned parallelepiped space to minimize empty spaces that might increase convection in the walls of the tank.

The first row of insulating elements 45 may be manufactured in different ways.

In one embodiment, the first row of insulating elements 45 is made in the form of a rigid block, such as a parallelepiped chamber, mainly made of plywood assembled together according to known techniques, and filled with an insulating lining, which may be made of different materials, such as glass wool, expanded perlite, expanded polystyrene or polymer foam. Alternatively, a plywood-high density polyurethane foam-plywood sandwich structure may be used as the rigid block.

In another embodiment, the first row of insulating elements 45 is made of a more flexible insulating material, such as glass wool or low density polymer foam, and has no structural function.

In a second step, the connecting

beam

17, 117, 217 is attached to the load-bearing structure parallel to the edge 101 by adjusting the two secondary anchoring flanges 33 in the direction of the secondary anchoring plate 31 by means of a plurality of length-adjustable fasteners 50, the fasteners 50 being placed between the two primary anchoring flanges 38 and the primary anchoring plates 30 of the first and second load-bearing walls 5, 25.

As shown in fig. 4, the length adjustable fasteners 50 may be distributed at regular intervals along the two primary anchor flanges 38 to balance the distribution of the load to minimize bending of the connecting

beam

17, 117, 217 at this stage. In the example shown, three length adjustable fasteners 50 are distributed along each primary anchor flange 38 of a cross beam section, for example of length 3 m.

It must be noted that the presence of the preassembled

insulating elements

40, 41 and/or 42 makes it possible to make the connecting beam more rigid, so as to minimize bending during this phase. Furthermore, if a rigid first row of insulating elements 45 has been used, during this step the two secondary anchoring flanges 33 of the connecting

beams

17, 117, 217 can be placed against the upper edge zones 49 of the first row of insulating elements 45, or if necessary the corner insulating elements 42 can be placed against the surface delimiting the recesses 44, which also makes it possible to limit the bending of the connecting

beams

17, 117, 217.

In this second step, if the first row of insulating elements 45 is not used as a support, for example if they are made of a flexible material, their previous arrangement is not necessary and the step indicated above as first step can also be performed subsequently.

In a third step, the length of the length adjustable fastener 50 is adjusted to adjust the distance and parallelism of the primary 36 or secondary 35 attachment flanges relative to the reference surface.

The reference surface may be obtained in various ways, for example with respect to a previously mounted beam section or with respect to a load bearing structure.

In the embodiment of fig. 2, the reference surface 51 is defined by the upper surface of a plurality of shims 52, said plurality of shims 52 being placed on at least one carrier wall, in this case on the first carrier wall 5, wherein the shims 52 are dimensioned in such a way that: the reference surface 51 has a better flatness than the flatness of the corresponding carrier wall 5. These spacers 52 serve to fill the gap of the carrier wall with respect to a perfectly flat theoretical surface, and the size of the spacers 52 can be determined optically.

In the embodiment of fig. 2, in order to adjust the distance and parallelism of the secondary connecting flange 35 with respect to the reference surface 51, an adjustment tool 53, in this case an L-shaped adjustment tool, is provided, which comprises a first surface 54 and a second surface 55, the second surface 55 being parallel to the first surface 54 and spaced from the first surface 54 by a predetermined distance a. The first surface 54 is brought into register with the reference surface 51 by placing the first surface 54 against the washer 52, and then the length of the length adjustable fastener 50 is adjusted until the secondary connecting flange 35 is placed against the second surface 55 of the adjustment tool 53.

In a fourth step, the two secondary anchoring flanges 33 are welded to the secondary anchoring plates 31 of the first and second load-bearing walls 5, 25 to secure the connecting

beam

17, 117, 217 to the load-bearing structure. Depending on the width of the secondary anchor flange 33, the weld joint may be formed directly between the secondary anchor flange 33 and the secondary anchor plate 31, or by a connecting plate 56 interposed between the secondary anchor flange 33 and the secondary anchor plate 31.

Once these weld joints are formed, the length adjustable fasteners 50 may be removed.

In a fifth step, a second row of insulating elements 57 (fig. 1) is placed in the two parallelepiped spaces 58 (fig. 2) between the primary and

secondary anchor plates

30, 31 of each of the first and second bearing walls 5, 25, to fill said parallelepiped spaces 58 in the thickness direction of the first and second tank walls 1, 2 up to the central core 32, or up to the lateral insulating elements 41 if the lateral insulating elements 41 have been preassembled at the central core 32. This filling of the parallelepiped space 58 makes it possible to stabilize the connecting

beams

17, 117, 217 by pressing against the second row of insulating elements 57.

In a fifth step, the two primary anchoring flanges 38 are fixed to the primary anchoring plates 30 of the first and second bearing walls 5, 25 by welding the connecting plates 59 (fig. 1) together. In other words, the connecting plate 59 replaces the length-adjustable fasteners 50 which serve only as temporary fastening of the connecting

beams

17, 117, 217.

If the connecting

beams

17, 117, 217 have not been pre-assembled with the central insulating element 40, the central insulating element 40 can be introduced and fixed in the central core 32 at this stage.

It can thus be seen that by ensuring the continuity of the secondary insulation and the primary insulation, the tank corner regions have been formed.

Some of the steps of the installation process described above may be performed in a different order than that mentioned in the present specification. Preferably, the length adjustable fastener is removed only after welding the two secondary anchor flanges to the secondary anchor plate. Preferably, the primary anchor flange is welded to the primary anchor plate only after removal of the length-adjustable fastener.

In order to ensure continuity of the degree of sealing of the primary membrane at the tank corners, the primary connecting flange 36 and the corners 37 of the connecting beams must be sealed along their entire length, even at the junction between successive lengths of connecting beams.

Similarly, in order to ensure the continuity of the tightness of the secondary membrane at the tank corners, the secondary connecting flanges 35, the sides 48 of the central core 32 and the corners 34 of the connecting beams must be sealed along their entire length, even at the junction between two successive sections of connecting beams.

In contrast, the other two sides of the central core 32 do not need to be sealed and, as illustrated in fig. 4 to 6, they may have a notch 19 at the end of a length of connecting beam. The recess 19 allows the introduction of a joint set to join two successive lengths of the connecting

beam

17, 117, 217 placed end to end.

In the embodiment shown, the angle between the carrier walls 1 and 2 has a value of 90 °. Other angular values are also possible, for example 135 °.

FIG. 3 illustrates an embodiment of a length-adjustable fastener. In this embodiment, the fastener 60 comprises a screw tensioning device comprising an actuating shank 64 and two coaxially arranged threaded

rods

61, 62, one end of the threaded

rods

61, 62 being screwed towards the centre of the fastener 60 and into two nuts 63 fixed to the actuating shank 64. An actuating handle 64 is rotatably mounted on the two threaded

rods

61, 62 such that the threaded

rods

61, 62 are closer to each other, and thus the length of the fastener 60, is reduced by rotating in one direction, and such that the threaded

rods

61, 62 are separated from each other, and thus the length of the fastener 60, is increased by rotating in the opposite direction. The two threaded

bars

61, 62 are welded or fixed at the other end to the base of two U-shaped fasteners 65, which two U-shaped fasteners 65 open towards the opposite direction to the screw tensioning device.

U-shaped fasteners 65 may be engaged on primary anchorage plate 30 and primary anchorage flange 38, respectively, and secured to primary anchorage plate 30 and primary anchorage flange 38, for example, by screws or pins 66. To this end, the required perforations are provided along the primary anchor plate and primary anchor flange 38.

Other techniques for attaching the adjustable length fastener are contemplated, such as by using a telescoping rod equipped with means for locking by clamping or snap-fit engagement.

Referring to fig. 7, a cut-away view of an LNG ship 70 shows a sealed and insulated storage tank 71 having a prismatic overall shape mounted in a double hull 72 of the ship. The walls of the storage tank 71 comprise a primary sealing barrier designed to be in contact with the LNG in the storage tank, a secondary sealing barrier placed between the primary sealing barrier and the double hull 72 of the vessel, and two thermal insulation barriers placed between the primary sealing barrier and the secondary sealing barrier and between the secondary sealing barrier and the double hull 72, respectively.

In a manner known per se, a loading/unloading line 73 on the upper deck of the vessel may be coupled to a marine or harbour terminal by means of suitable connectors for transferring LNG cargo into the storage tank 71 or for transferring LNG cargo out of the storage tank 71.

Figure 7 shows an example of a marine terminal comprising a loading and unloading station 75, a subsea pipeline 76 and an onshore facility 77. The loading and unloading station 75 is an offshore fixed installation comprising a movable arm 74 and a column 78 supporting the movable arm 74. The movable arm 74 houses an insulated flexible tube bundle 79 that can be connected to the loading/unloading line 73. The adjustable movable arm 74 is suitable for all LNG carrier sizes. A connecting tube (not shown) extends inside the post 78. The loading and unloading station 75 allows the LNG carrier vessel 70 to be loaded or unloaded from the onshore facility 77 to the onshore facility 77. The installation comprises a liquefied gas storage tank 80 and a connection pipe 1081 connected to a loading or unloading station 75 through a subsea pipeline 76. The subsea pipeline 76 transfers liquefied gas over a long distance, e.g., 5km, between the loading or unloading station 75 and the onshore facility 77, which makes it possible to hold the LNG carrier vessel 70 at a long distance from shore during loading and unloading operations.

To generate the pressure required for transferring the liquefied gas, pumps onboard the vessel 70 and/or pumps mounted on onshore facilities 77 and/or pumps mounted on the loading and unloading station 75 are used.

Although the invention has been described in connection with several specific embodiments, it is evident that the invention is in no way limited thereto and that the invention encompasses all technical equivalents of the means described as well as combinations thereof, provided that such technical equivalents and combinations are within the scope of the invention.

Use of the verb "comprise", "consist of" or "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The use of the indefinite article "a" or "an" for an element or step does not exclude the presence of a plurality of such elements or steps, unless otherwise indicated.

Claims

1. A method of installing an anchoring device for a sealed and thermally insulated storage tank (71) for storing a fluid, the storage tank comprising a plurality of tank walls (1, 2), wherein each tank wall (1, 2) comprises in the thickness direction a load-bearing wall (5, 25), a secondary thermally insulating barrier (6, 26) anchored to the load-bearing wall (5, 25), a secondary sealing membrane (7, 27) parallel to the load-bearing wall (5, 25), a primary thermally insulating barrier (8, 28) and a primary sealing membrane (9, 29) parallel to the load-bearing wall (5, 25) and designed to be in contact with the fluid in the storage tank; wherein the method comprises:

providing a load-bearing structure (90), the load-bearing structure (90) having a first load-bearing wall (5) and a second load-bearing wall (25) that meet at an edge (101), wherein each of the first and second load-bearing walls has a primary anchor plate (30) and a secondary anchor plate (31) that protrude towards the inside of the tank and are arranged parallel to the edge such that the distance between the secondary anchor plate (31) and the edge (101) corresponds to the thickness of the secondary thermal barrier and the distance between the primary anchor plate (30) and the secondary anchor plate (31) corresponds to the thickness of the primary thermal barrier,

providing a connecting beam (17, 117, 217), said connecting beam (17, 117, 217) consisting of a flat metal sheet,

attaching the connecting beam (17, 117, 217) to the load-bearing structure parallel to the edge (101) by adjusting two secondary anchoring flanges (33) in the direction of the secondary anchoring plates (31, 31) of the first and second load-bearing walls by means of a plurality of length-adjustable fasteners (50, 60) placed between two primary anchoring flanges (38) and the primary anchoring plates (30, 30) of the first and second load-bearing walls,

adjusting the length of the length-adjustable fasteners (50, 60) to adjust the distance and parallelism of the primary (36) or secondary (35) attachment flanges relative to a reference surface (51), an

Welding two of the secondary anchoring flanges (33) to the secondary anchoring plates (31) of the first and second load-bearing walls to secure the connecting beam to the load-bearing structure,

removing the length-adjustable fastener (50, 60),

-fixing the two primary anchoring flanges (38) to the primary anchoring plates (30) of the first and second load-bearing walls by welding together connecting plates (59);

wherein the flat metal sheets are welded together to form:

a hollow central core (32), said central core (32) having a parallelogram cross-section, said central core having a first corner having the same value as the angle between said first and second load-bearing walls, a first side having a length equal to the distance between the primary anchor plate of said first load-bearing wall and the secondary anchor plate of said first load-bearing wall, and a second side having a length equal to the distance between the primary anchor plate of said second load-bearing wall and the secondary anchor plate of said second load-bearing wall,

two of said secondary anchoring flanges (33), said secondary anchoring flanges (33) protruding from said first corner (34) of said central core towards the outside of said central core (32) and being aligned with two sides (48) of said central core that meet at said first corner,

two of said secondary connecting flanges (35), said secondary connecting flanges (35) projecting with respect to the central core towards the outside of the central core (32) in the opposite direction to the secondary anchoring flanges (33) and also being aligned with said two sides (48) of the central core that intersect at said first corner,

two of said primary connecting flanges (36), said primary connecting flanges (36) protruding from a second corner (37) of the central core towards the outside of the central core and being aligned with two sides of the central core that meet at the second corner (37), wherein the second corner is diagonally opposite to the first corner (34) of the central core, and

two of said primary anchoring flanges (38), said primary anchoring flanges (38) projecting with respect to said central core towards the outside of said central core in the opposite direction to said primary connecting flanges (36) and also being aligned with two sides of said central core that meet at said second corner (37).

2. The method of claim 1, further comprising:

-fixing a central insulating element (40) in the central core (32) before attaching the connecting beams (117, 217) to the load-bearing structure.

3. The method of one of claims 1 to 2, further comprising:

-before attaching the connecting beam (117) to the load-bearing structure, placing side insulating elements (41) outside the central core along two sides (48) of the central core that meet at the first corner (34), such that the side insulating elements (41) thereby fill two spaces between the secondary anchoring flange (33) and the primary anchoring flange (38) respectively along each of the two sides of the central core, and-fixing the side insulating elements to the primary and secondary anchoring flanges.

4. The method of claim 3, further comprising:

-before fixing the two primary anchoring flanges (38) to the primary anchoring panels (30) of the first and second bearing walls, placing a second row of insulating elements (57) in two parallelepipedic spaces (58) between the primary (30) and secondary (31) anchoring panels of each of the first and second bearing walls, to fill the parallelepipedic spaces in the thickness direction of the first and second tank walls up to the side insulating elements (41), thereby stabilizing the connecting beam by pressing against the second row of insulating elements (57).

5. The method of one of claims 1 to 2, further comprising:

-before fixing the two primary anchoring flanges to the primary anchoring panels of the first and second bearing walls, placing a second row of insulating elements (57) in the two parallelepiped spaces between the primary anchoring panels (30) and the secondary anchoring panels (31) of each of the first and second bearing walls to fill the parallelepiped spaces in the thickness direction of the first and second tank walls up to the central core (32), thereby stabilizing the connecting beam by pressing against the second row of insulating elements (57).

6. The method of one of claims 1 to 2, further comprising:

-before attaching the connecting beam (217) to the load-bearing structure, placing corner insulating elements (42) along the first corners (34) of the central core outside the central core (32) between the two secondary anchoring flanges (33), and-fixing the corner insulating elements to the two secondary anchoring flanges.

7. The method of claim 6, further comprising:

-before attaching the connecting beam (217) to the load-bearing structure, placing a first row of insulating elements (45) in the parallelepiped space between an end portion of the first load-bearing wall and an end portion of the second load-bearing wall, wherein the end portions are located between the secondary anchor plate (31) and the edge of the first load-bearing wall and between the secondary anchor plate (31) and the edge of the second load-bearing wall, the first row of insulating elements (45) being formed with recesses (44) to accommodate the corner insulating elements (42) while attaching the connecting beam (217) to the load-bearing structure parallel to the edge.

8. The method of one of claims 1 to 2, further comprising:

-before attaching the connecting beam (17, 117) to the load-bearing structure, placing a first row of insulating elements (45) in the parallelepiped space between an end portion of the first load-bearing wall and an end portion of the second load-bearing wall, wherein the end portions are located between the secondary anchoring plate (31) of the first load-bearing wall and the edge and between the secondary anchoring plate (31) of the second load-bearing wall and the edge.

9. Method according to one of claims 1 to 2, wherein the reference surface (51) is defined by the upper surfaces of a plurality of shims (52) placed on the first or second carrier wall, wherein the shims are dimensioned such that the reference surface has a better flatness than the first or second carrier wall.

10. The method of claim 9, wherein the step of adjusting the distance and parallelism of the primary or secondary connecting flanges relative to the reference surface comprises:

providing an adjustment means (53), said adjustment means (53) having a first surface (54) and a second surface (55), said second surface (55) being parallel to said first surface and spaced from said first surface by a predetermined distance,

keeping the first surface (54) of the adjustment tool pressed against the pad,

adjusting the length of the length-adjustable fastener until the primary or secondary connecting flange (36, 35) is placed against the second surface (55) of the adjustment tool.