Patent Application
20210071817
The invention relates to the field of corrugated metal membrane fluid-tight tanks for the storage and/or the transportation of a fluid, and in particular to fluid-tight and thermally insulative tanks for liquefied gas.
The invention relates in particular to the field of fluid-tight and thermally insulative tanks for the storage and/or the transportation of liquid at low temperature, such as tanks for the transportation of liquefied petroleum gas (LPG) at for example a temperature between −50° C. and 0° C. inclusive, or for the transportation of liquefied natural gas (LNG) at approximately −162° C. at atmospheric pressure. These tanks may be installed on land or on a floating structure. In the case of a floating structure, the tank may be intended for the transportation of liquefied gas or to receive liquefied gas serving as fuel for propelling the floating structure.
There is described in FR-A-2936784 a corrugated fluid-tight membrane tank reinforced by means of wave reinforcements disposed under the corrugations, between the sealing membrane and the support of that sealing membrane, to reduce the stresses in the sealing membrane caused by a multitude of factors, including thermal shrinkage on cooling the tank, the effect of flexing of the beam of the ship, and the dynamic pressure caused by movement of the cargo, in particular because of the swell.
In a tank of this kind, the sealing membrane features two perpendicular series of corrugations. The fluid-tight membrane therefore features a plurality of nodes corresponding to the intersections between the corrugations of the series of corrugations.
In one embodiment, these reinforcing parts, also termed wave reinforcements, are hollow and allow the gas to circulate between the corrugations and the support via the reinforcing parts, notably for inerting the insulative barrier or detecting leaks. These reinforcing parts are arranged under the corrugations and between two successive nodes and are therefore interrupted at the level of said nodes.
However, the applicant has realized that the stresses in the sealing membrane are not necessarily uniform in the tank. Thus the same corrugation may be subjected to asymmetrical stresses that can generate deformations of the membrane for which the reinforcing parts do not provide an adequate membrane reinforcement function. In particular, the applicant has realized that the reinforcing parts are subjected to conjoint displacements with the corrugation portion in which they are accommodated when said corrugation is subjected to asymmetrical stresses. This conjoint displacement of the reinforcement part and the corrugation can generate torsion of the membrane at the level of the node.
A basic idea of the invention is to provide a corrugated sealing membrane fluid-tight wall reinforced continuously along the corrugation. A basic idea of the invention is to ensure continuity of the wave reinforcements arranged in a corrugation. A basic idea of the invention is to ensure alignment of the wave reinforcements arranged under a corrugation to limit the risks of torsion of the membrane at the level of the node. Thus, a basic idea of the invention is to preserve an alignment of the wave reinforcements arranged under the successive portions of a corrugation corresponding to a longitudinal direction of said corrugation. In particular, a basic idea of the invention is to preserve the wave reinforcements arranged under a corrugation on either side of a node and aligned in the longitudinal direction of said corrugation.
In accordance with one embodiment, the invention provides a fluid-tight tank wall including a corrugated fluid-tight membrane, the corrugated fluid-tight membrane including a first series of parallel corrugations and a second series of parallel corrugations and plane portions situated between the corrugations and intended to rest on a support surface, said first and second series of corrugations extending in intersecting directions and forming a plurality of nodes at the crossings of said corrugations,
wave reinforcements being arranged under the corrugations of the first series of corrugations,
two successive wave reinforcements in a corrugation each including a sole intended to rest on the support surface and a reinforcement portion disposed above the sole in a thickness direction of the tank wall, the two wave reinforcements being developed longitudinally in the corrugation on either side of a node,
said soles being hollow, a connecting member extending in the corrugation at the level of the node and being nested in the soles of said two wave reinforcements in such a manner as to assemble the two wave reinforcements in an aligned position.
Thanks to these features, continuity is ensured between two successive wave reinforcements arranged in a corrugation on either side of a node. Thanks to these features, the relative movement between two successive wave reinforcements arranged in the corrugation is limited, including in the presence of asymmetrical stresses on either side of the node and/or on either side of a corrugation. In particular, two successive wave reinforcements arranged under the corrugation are kept aligned in the longitudinal direction of the corrugation. Thus a portion of the corrugation situated on one side of the node is supported effectively by the wave reinforcement arranged under said corrugation portion, said wave reinforcement being retained in position by cooperation with the adjacent wave reinforcement via the connecting member.
Embodiments of such a wall may have one or more of the following features.
In one embodiment, the sole of one or each of said wave reinforcements features a respective projecting portion projecting longitudinally from the reinforcement portion of said wave reinforcement in the direction of the other wave reinforcement in such a manner to be engaged in the node.
Also, wave reinforcements of this kind are simple to fabricate, the projecting portion of the sole being fabricated, for example, from an extruded reinforcement part, simply by eliminating the reinforcement portion of the wave reinforcement at the level of said projecting portion.
In one embodiment, one end of the connecting member features a section of identical size and shape to the hollow section of the sole in which said end is accommodated, to achieve nesting with no significant play. In other words, the connecting member is nested and guided longitudinally in the soles with a simple assembly clearance so that the position of the two wave reinforcements is aligned without significant angular play.
The wave reinforcement is preferably mounted to slide relative to the support and said corrugation. Thus thermal contraction of the wave reinforcement can be produced without formation of local stresses. Moreover, the longitudinal nesting of the connecting member in the sole of the wave reinforcement also enables thermal contraction of the wave reinforcement and of the connecting member without producing local stresses.
In one embodiment, at least one of said wave reinforcements is associated with an attached spacer engaged in said node, an end face of the attached spacer opposite the node forming an abutment surface for an end face of the wave reinforcement facing the node, said attached spacer including a passage extending the hollow section of the sole of the wave reinforcement in the direction of the other wave reinforcement and having the connecting member passed through it.
In one embodiment, the attached spacer is fixed to the connecting member.
The sole of the wave reinforcement forms a bottom part of the wave reinforcement and the reinforcement portion forms a top part of the wave reinforcement. The sole and the reinforcement portion may be separated by a plane or non-plane internal wall. They may also not be separated. In one embodiment, the sole of one of said wave reinforcements includes a lower wall intended to rest on the support surface. In one embodiment, the sole of one of said wave reinforcements further includes an upper wall parallel to the lower wall intended to rest on the support surface, the reinforcement portion of said wave reinforcement extending over the upper wall of the sole.
In one embodiment, the sole is open on the reinforcement portion. In other words, a hollow internal housing of the sole in which the end of the connecting member is nested is open on the reinforcement portion.
In one embodiment, the wave reinforcement has an internal surface that is developed parallel to the lower wall of the sole and delimits the hollow housing of the sole.
This internal surface may be produced in numerous ways.
In one embodiment, this internal surface is formed by a face of the internal wall separating the reinforcement portion from the sole.
In one embodiment, this internal surface is formed by an end surface of an internal rib of the reinforcement portion. In one embodiment, this internal rib is developed in a plane parallel to the thickness direction of the tank wall from an internal web of the reinforcement portion, for example from an intersection zone between two internal webs accommodated in the reinforcement portion.
In one embodiment, this internal surface is formed by one or more lateral portions of an upper wall of the sole, said lateral portions being developed parallel to the lower wall from lateral walls of the wave reinforcement.
In one embodiment, one end of the connecting member nested in said sole features a plane, for example rectangular or trapezoidal, section extending parallel to said lower wall. Thanks to these features, the moment of inertia of the connecting member about a bending axis parallel to the thickness direction of the tank wall is relatively high.
Preferably in this case, one end of the connecting member nested in the sole has a width, measured in a width direction perpendicular to the thickness direction of the tank wall and perpendicular to the longitudinal direction of the corrugation, greater than the thickness of said end of the connecting member, measured in the thickness direction of the tank wall.
In one embodiment, the width of the end of the connecting member nested in the sole is greater than half the width of the wave reinforcement in said width direction. Such a width of the end of the connecting member allows good rigidity in response to the lateral stresses, that is to say in said width direction.
In one embodiment, the hollow portion of the sole has a plane section parallel to the support surface when the lower wall of said sole rests on said support surface. In other words, the hollow portion of the sole has a width measured in a direction perpendicular to the longitudinal direction of the corrugation and perpendicular to the thickness direction of the tank wall greater than the thickness of said hollow portion measured in the thickness direction of the tank wall.
In one embodiment, the end of the connecting member 13 is nested in the sole over a distance of 2 to 3 cm, or, preferably, over a distance greater than 5 cm, notably from 5 to 8 cm. Such an insertion direction ensures a large cooperation zone between the connecting member and the wave reinforcement, thus allowing and ensuring stable maintenance of the alignment between the wave reinforcements and good distribution of the lateral stresses over an extensive cooperation zone.
In one embodiment, said connecting member is a plane part that has a uniform thickness.
The connecting member in the form of a plane, that is to say thin, part has a low overall size in the thickness direction of the tank wall and is therefore able to pass under the fluid-tight membrane at the level of the node without interfering with the corrugations of the fluid-tight membrane.
In one embodiment, the soles have two internal walls developed in the thickness direction, said internal walls delimiting with the lower wall, and where applicable the upper wall, the hollow portion of the sole. In one embodiment, the hollow portion of the sole features a section of rectangular shape.
In one embodiment, the node includes a summit, said corrugation including on either side of the summit a concave portion forming a constriction of the corrugation, said projecting portion and/or the attached spacer extending in the node as far as the constriction of the corrugation situated on the corresponding side of the summit or beyond said constriction of the corrugation.
Said constriction defines for example a minimum section of the corrugation in the node.
In one embodiment, the connecting member includes an abutment surface adapted to limit the insertion of the connecting member into one of said soles.
In one embodiment, the abutment surface is a first abutment surface adapted to limit the insertion of the connecting member into one of the soles and the connecting member includes a second abutment surface adapted to limit the insertion of the connecting member in the other sole.
Abutment surfaces of this kind may be produced in numerous ways. In one embodiment, the connecting member includes an overthickness and/or an overwidth, the connecting member featuring at the level of said overthickness and/or overwidth a section the dimensions of which are greater than the dimensions of the hollow portion of the sole or soles, said overthickness and/or an overwidth carrying the abutment surface or surfaces. In one embodiment, the connecting member has a central portion having a uniform section in the longitudinal direction of the corrugation, the abutment surface or surfaces being formed by an attached part fixed to said central portion. This attached part may be produced in numerous ways, for example as a screw, a rivet, a nail fixed to the central portion of the connecting member, preferably without passing through it. This attached part may equally be a metal part fixed to the central portion of the connecting member. A metal part of this kind, being adapted to serve as an abutment for the first wave reinforcements, is for example a connecting part carrying connecting lugs intended to cooperate with the second wave reinforcements accommodated in the second corrugations.
In one embodiment, the connecting member is mounted to slide relative to the support surface, for example a thermal insulation barrier. In other words, the connecting member is not fixed to the thermal insulation barrier. Thus when neither the wave reinforcements nor the connecting members are fixed to the support surface, the wave reinforcements and the connecting members may be retained in position between the fluid-tight membrane and the support surface by virtue of the nesting between the wave reinforcements and the connecting member and the fixing of the fluid-tight membrane to the support surface, for example by welding.
In one embodiment, the wave reinforcements arranged under the corrugations of the first series of corrugations are first wave reinforcements, the tank further including second wave reinforcements arranged under corrugations of the second series of corrugations, two second wave reinforcements being disposed in the corrugation of the second series of corrugations forming the node on either side of said node.
In one embodiment, a second wave reinforcement extends between two successive nodes of a corrugation.
In one embodiment, the distance between the ends of the soles and/or between the ends of the attached spacers of the first two wave reinforcements is greater than a width of the second wave reinforcements arranged in the corrugation of the second series of corrugations forming the node, the connecting member including a central portion inserted between the soles of said first two wave reinforcements.
In one embodiment, the second reinforcements adjacent to the node have one end accommodated in the node in contact with the connecting member. Thanks to these features, the connecting member exercises an abutment function therefore limiting the movement of the second wave reinforcements in the longitudinal direction of the second corrugations.
In one embodiment, the second wave reinforcements are hollow, the connecting member including a central portion inserted between the soles of the first wave reinforcements, the connecting member further including two lugs, each of said two lugs projecting from the central portion of the connecting member in a longitudinal direction of the second series of corrugations and penetrating into a respective second wave reinforcement.
In one embodiment, the lugs are elastic lugs adapted to exert a force in a direction away from the fluid-tight membrane to press said second wave reinforcements onto the support surface.
In one embodiment, the two lugs are nested in the second wave reinforcements in such a manner as to assemble said two second wave reinforcements to the connecting member. For example, in this case the connecting member has a cruciform shape of which said lugs and said ends of the connecting member form four branches. The cruciform plane connecting member may be produced in the form of a plane part.
In one embodiment, the connecting member includes a cruciform plane part, said lugs and said ends of the connecting member forming four branches of the cross.
In one embodiment, the lugs and the central portion are of monobloc construction.
In one embodiment, an end of one of said lugs distant from the central portion includes a retaining member adapted to retain the second wave reinforcement in position.
A retaining member of this kind may be produced in numerous ways. In one embodiment, the second wave reinforcements include a mounting tab in their hollow portion, the end of the lugs being configured to cooperate with this tab in order to retain the second reinforcements. In one embodiment, the second wave reinforcements include internal webs, the end of the lugs being configured to be fixed, for example clipped, to an edge surface of said internal webs facing the node.
In one embodiment, the connecting member further includes a retaining plate fixed to the central portion of the connecting member, the plate carrying the lugs.
In one embodiment, the connecting member includes a fixing member of the plate, said fixing member being fixed in the base at a distance from the thermally insulative barrier.
In one embodiment, respective second wave reinforcements each include a hollow sole intended to rest on the support surface and a reinforcement portion disposed above the sole in the direction of the thickness of the tank wall. In this case, the two lugs of the connecting member may be nested longitudinally in said soles. This results in an assembly device of relatively small overall size in the direction of the thickness of the wall.
In one embodiment, the reinforcement portion of the wave reinforcement the sole of which includes said projecting portion has a bevelled end in the direction of the node.
In one embodiment, the reinforcement portion of the wave reinforcements has an external wall, for example of semi-elliptical convex external shape, delimiting an internal space of the reinforcement portion, the reinforcement portion further including internal reinforcement webs.
In one embodiment, such internal webs are developed between a respective sole upper wall lateral portion and an internal face of the external wall of the reinforcement portion.
In one embodiment, the reinforcement portion of the wave reinforcements has an external wall, an end of said external wall facing the node forming an edge surface of said external wall, said edge surface being bevelled in such a manner as to have a face inclined relative to a plane perpendicular to the longitudinal direction of the corrugation and facing toward the corrugation.
In one embodiment, the corrugated fluid-tight membrane includes a corrugated rectangular sheetmetal part, said first series of corrugations extending in a lengthwise direction of the sheetmetal part, said second series of corrugations extending in a widthwise direction of the sheetmetal part,
and the wave reinforcements arranged under a corrugation of the first series of corrugations include a row of aligned wave reinforcements, said row of wave reinforcements being developed over all the length of the rectangular sheetmetal part, said wave reinforcements each including a hollow sole and a reinforcement portion and being assembled two by two by a plurality of connecting members nested in the soles of the successive wave reinforcements at the level of the nodes.
In one embodiment, the corrugated fluid-tight membrane includes a corrugated rectangular sheetmetal part, said first series of corrugations extending in a lengthwise direction of the sheetmetal part, said second series of corrugations extending in a widthwise direction of the sheetmetal part,
and the wave reinforcements arranged under a corrugation of the first series of corrugations include a row of aligned wave reinforcements, said row of wave reinforcements being developed over substantially all the length of the rectangular sheetmetal part, said wave reinforcements each including a hollow sole including a lower wall intended to rest on the support surface and a reinforcement portion disposed above the sole, and being assembled two by two by a plurality of connecting members nested in the soles of the successive wave reinforcements at the level of the nodes of said corrugation.
In one embodiment, the two ends of the row of wave reinforcements are fixed, for example clipped, to the edges of the rectangular sheetmetal part delimiting the corrugation. It is therefore possible to handle the sheetmetal part with one or more rows of wave reinforcements preassembled thereto in this way, which facilitates the assembly of a tank wall.
In one embodiment, a plurality of rows of wave reinforcements constituted in the same manner are arranged in the respective corrugations of the first series of corrugations over all the length of the rectangular sheetmetal part, for example in each of the corrugations or in only some of them, and may be fixed to the rectangular sheetmetal part in the same manner.
In one embodiment, rows of wave reinforcements are arranged in the corrugations of the second series of corrugations. These wave reinforcements may be fixed in various ways, for example by cooperation with the connecting members. In one embodiment, the wave reinforcements arranged in the corrugations of the second series of corrugations are fixed to the corrugated sheetmetal part, for example by means of double-sided adhesive tape or by gluing.
In one embodiment, a plurality of rows of wave reinforcements are arranged in the respective corrugations of the first series of corrugations over substantially all the length of the rectangular sheetmetal part and rows of second wave reinforcements are arranged in the corrugations of the second series of corrugations, the second wave reinforcements being assembled to the first wave reinforcements by cooperation with the cruciform connecting members at the level of the nodes to form a framework of the corrugated rectangular sheetmetal part.
A framework of this kind may be pre-assembled onto the external surface of the rectangular sheetmetal part and fixed to the latter as indicated above. A framework of this kind may also be preassembled independently of the rectangular sheetmetal part intended to receive it, for example by means of a mounting frame. The preassembly of a framework of this kind facilitates the assembly of the tank wall by limiting handling operations.
In one embodiment, the fluid-tight membrane includes a second corrugated rectangular sheetmetal part juxtaposed to the first corrugated rectangular sheetmetal part in the lengthwise direction and welded to the latter in fluid-tight manner,
the second corrugated rectangular sheetmetal part being provided with a second framework formed of first and second wave reinforcements arranged in the corrugations of the second corrugated rectangular sheetmetal part and assembled by a plurality of connecting members nested in said wave reinforcements at the level of the nodes of the second corrugated rectangular sheetmetal part.
A first end reinforcement forming the end of a row of first wave reinforcements of the first framework may be associated with a second end reinforcement forming the end of a row of first wave reinforcements of the second framework by a connecting sleeve, the first and second end reinforcements each including a longitudinal housing opening onto a lower surface of the end reinforcement, the connecting sleeve being nested in the longitudinal housing of the first and second end reinforcements in such a manner as to align the row of wave reinforcements of the first framework and the row of wave reinforcements of the second framework.
In one embodiment, the invention also provides an assembly forming a preassembled framework for membranes, said framework including wave reinforcements intended to be accommodated under corrugations of a corrugated sealing membrane including two series of intersecting corrugations, one of said wave corrugations including a plane lower surface intended to rest on a support surface and an internal housing adjacent to the lower wall,
said framework including with a plurality of rows of aligned first wave reinforcements, each row being intended to be accommodated under a corrugation of the first series of corrugations of the fluid-tight membrane,
said framework including a plurality of rows of aligned second wave reinforcements, each row being intended to be accommodated under a corrugation of the second series of corrugations of the sealing membrane,
said framework further including a plurality of cruciform connecting members including lugs accommodated in the housings of the first and second wave reinforcements at the level of the intersection of the rows of first wave reinforcements and the rows of second wave reinforcements,
said assembly further including an assembly frame arranged around ends of the rows of wave reinforcements and including attachments cooperating with end reinforcements arranged at the ends of the rows of first wave reinforcements and the rows of second wave reinforcements in such a manner as to retain the assembly in an assembled state.
In a preassembled framework of this kind the wave reinforcements are assembled by the cruciform connecting members and by the assembly frame in the form of a lattice of wave reinforcements.
In one embodiment, the end first wave reinforcements and the end second wave reinforcements include an open housing opening onto the lower surface of said end first and second wave reinforcements.
In one embodiment, the assembly frame is replaced by a corrugated metal plate intended to form a portion of the sealing membrane and the attachments are arranged at the edges of the metal plate.
In one embodiment, the invention also provides a fluid-tight tank wall assembly method for assembling a tank wall including the steps of:
In one embodiment, the step of retaining the ends of the row of first wave reinforcements includes the steps of
In one embodiment, the step of retaining the ends of the row of first wave reinforcements includes the step of fixing a fixing rail to the support surface, said fixing rail cooperating with an end first wave reinforcement of the row of first wave reinforcements to retain the corresponding end of the row of first wave reinforcements on the support surface.
In one embodiment, the method further includes a step of removing the fixing rail from the support surface.
In one embodiment, the fixing rail cooperates with the end of a plurality of rows of adjacent first wave reinforcements positioned on the support surface in order to stabilize the position of said rows of first wave reinforcements.
In one embodiment, the step of positioning the second wave reinforcements includes the step of nesting said second wave reinforcements in adjacent connecting members of two rows of adjacent first wave reinforcements.
In one embodiment, the step of anchoring the corrugated rectangular sheetmetal part to the support surface includes the step of welding said corrugated rectangular sheetmetal part to a corrugated rectangular sheetmetal part previously anchored to the thermally insulative barrier.
In one embodiment, the invention also provides a wave reinforcement intended to be accommodated under a corrugation of a corrugated sealing membrane, the wave reinforcement including a hollow sole and a hollow reinforcement portion disposed above said sole, the sole including a plane lower wall intended to rest on a support surface and an upper wall separating the sole from the reinforcement portion and parallel to said lower surface, the lower wall and the upper wall being connected by lateral walls of the sole, the reinforcement portion including an external wall extending above the sole, said external wall delimiting with the upper wall of the sole an internal space of the reinforcement portion.
Embodiments of a wave reinforcement of this kind may include one or more of the following features.
In one embodiment, the wave reinforcement further includes an internal web arranged in the internal space of the reinforcement portion. In one embodiment, this internal web features a circular shape truncated by the upper wall of the sole, said internal web being tangential to the external wall on either side of the summit of said external wall.
In one embodiment, the sole features a projecting portion projecting longitudinally relative to the reinforcement portion at the level of at least one longitudinal end of the wave reinforcement.
In one embodiment, the invention also provides a wave reinforcement intended to be accommodated under a corrugation of a fluid-tight and thermally insulative tank sealing membrane, said wave reinforcement including a plane wall intended to rest on a support surface and an external wall conjointly delimiting therewith an internal space of said wave reinforcement, the wave reinforcement further including in said internal space an internal web having a circular shape truncated by the plane wall, said internal web being tangential to the external wall on either side of a summit of said external wall.
In one embodiment, the external wall has a semi-elliptical convex shape.
A tank wall of this kind may form part of a land storage installation, for example for storage of LNG, or be installed on a floating structure, for coastal or deep water use, notably a methane tanker ship or any ship using a combustible liquefied gas as a fuel, a Floating Storage and Regassification Unit (FSRU), a Floating Production Storage and Offloading (FPSO) installation, etc.
In one embodiment, the invention provides a ship for the transportation of a cold liquid product that includes a double hull and a tank including the aforementioned fluid-tight wall disposed in the double hull.
In one embodiment, the invention also provides a method of loading or offloading a ship of this kind, in which a cold liquid product is fed through insulated pipes from or to a floating or land storage installation to or from the tank of the ship.
In one embodiment, the invention also provides a cold liquid product transfer system, the system including the aforementioned ship, insulated pipes adapted to connect the tank installed in the hull of the ship to a floating or land storage installation and a pump for driving a flow of cold liquid product through the insulated pipes from or to the floating or land storage installation to or from the tank of the ship.
The invention will be better understood, and other aims, details, features and advantages thereof will become more clearly apparent in the course of the following description of particular embodiments of the invention, provided by way of nonlimiting illustration only, with reference to the appended drawings.
By convention, the terms “external” and “internal” are used to define the position of one element relative to another one, with reference to the interior and the exterior of the tank.
A fluid-tight and thermally insulative tank for the storage and the transportation of a cryogenic fluid, for example liquefied natural gas (LNG), includes a plurality of tank walls each having a multilayer structure.
A tank wall of this kind includes, from the exterior to the interior of the tank, a thermal insulation barrier anchored to a supporting structure by retaining members and a sealing membrane carried by the thermal insulation barrier and intended to be in contact with the cryogenic fluid contained in the tank.
The supporting structure may in particular be a self-supporting metal plate or, more generally, any type of rigid partition having appropriate mechanical properties. The supporting structure may in particular be formed by the hull or the double hull of a ship. The supporting structure includes a plurality of walls defining the general shape of the tank, usually a polyhedral shape.
The tank may also include a plurality of thermal insulation barriers and sealing membranes. For example, from the exterior to the interior of the tank, a tank may include a secondary thermal insulation barrier anchored to the supporting structure, a secondary sealing membrane carried by the secondary thermal insulation barrier, a primary thermal insulation barrier resting on the secondary sealing membrane and a primary sealing membrane resting on the primary thermal insulation barrier. The thermal insulation barrier may be produced in numerous ways, in numerous materials and by known techniques such as, for example, described in the document WO2017017337 or WO2017006044. The sealing membranes may consist of corrugated rectangular metal parts including series of corrugations of different or similar sizes.
A node 5 includes a fold 7 that extends the top edge surface 8 (see
Other possible features and details of the sealing membrane 1, the corrugated metal plates forming said sealing membrane 1 and the structure of the nodes 5 are described in the document WO2017017337 or WO 2017006044. For example, the sealing membrane 1 may be made of stainless steel or aluminium sheet and have a thickness of approximately 1.2 mm and may be shaped by drawing or bending. Other metals or alloys and other thicknesses are possible.
As shown in
The first wave reinforcements 11 are arranged under each longitudinal portion 6 of the high corrugations 3. Similarly, the second wave reinforcements 12 are arranged under each longitudinal portion 6 of the low corrugations 4.
However, the stresses in the tank are not always uniform. Thus a high corrugation 3 may be subjected over its length to asymmetrical stresses. Such asymmetrical stresses are reflected in the application of a lateral stress to a longitudinal portion 6 of the high corrugation 3 without the adjacent longitudinal portion 6 of said high corrugation 3 being subjected to any analogous stress. In the presence of asymmetrical stresses of this kind, the high corrugation 3 may be subject to a high torsion at the level of the node 5 separating the two successive longitudinal portions 6 subject to said asymmetrical stress.
To prevent this, as explained in more detail hereinafter with reference to
Connecting members 13 of this kind enable stable alignment of two successive first wave reinforcements 11. Thus each high corrugation 3 is supported by a row of first wave reinforcements 11 associated two by two along said high corrugation 3 in an alignment corresponding to the longitudinal direction of said high corrugation 3. Thus if a high corrugation 3 is subjected to an asymmetrical stress the connecting member 13 enables the alignment of the successive first wave reinforcements 11 to be preserved and therefore makes it possible to avoid torsion of the sealing membrane 1 at the level of the node 5. In particular, the first wave reinforcement 11 arranged under the longitudinal portion 6 subjected to a stress transmits part of the force to the first wave reinforcements 11 to which it is connected via the connecting members 13, thus enabling distribution of said force over the adjacent first wave reinforcements 11. In other words, the connecting members 13 enable the row of first wave reinforcements 11 to function in a substantially analogous manner in the presence of asymmetrical stresses and symmetrical stresses along the high corrugation 3 under which said row of first wave reinforcements 11 is arranged. Thus the high corrugations 3 are reinforced in a uniform manner over all their length and the risks of high torsion in the event of asymmetrical stresses are reduced or even eliminated.
As shown in
The first wave reinforcements 11 are described hereinafter with reference to
The sole 15 has a lower wall 17, two lateral walls 18 and an upper wall 19. The lower wall 17 is plane and rests on the thermal insulation barrier 2. The upper wall 19 is plane and parallel to the lower wall 17. The lateral walls connect the lower wall 17 and the upper wall 19 over all the length of the first wave reinforcement 11. The lower wall 17, the lateral wall 18 and the upper wall 19 conjointly delimit a hollow internal space of the sole 15.
As shown in
The reinforcement portion 16 of the first wave reinforcement 11 includes an external wall 22. This external wall 22 preferably has a shape complementary to the shape of the high corrugation 3. Thus, as shown in
The reinforcement portion 16 is preferably hollow in order to enable the circulation of inerting gas or leak detection gas in the thermal insulation barrier 2. Thus the upper wall 19 of the sole 15 and the external wall 22 together delimit a hollow internal space of the reinforcement portion 16.
The reinforcement portion 16 advantageously includes internal webs 23 in order to reinforce said reinforcement portion 16. In
The sole 15 has a length greater than the length of the reinforcement portion 16. Thus, as shown in
The first wave reinforcement 11 may be fabricated in many ways. The first reinforcement portion 11 is preferably produced initially with a constant section by extrusion of all the length of said first wave reinforcement 11. Thereafter, the reinforcement portion 16 is machined to produce the projecting portion 24 of the sole 15. The reinforcement portion 16 is preferably machined with a bevel at the level of its junction with the projecting portion 24, the reinforcement portion therefore having a maximum length at the level of its junction with the sole 15.
The length of the reinforcement portion 16 at the summit of the external wall 22 is for example equal to the length of the longitudinal portion 6 of the high corrugation 3 which has a uniform section between two nodes 5. This uniform section portion stops where the high corrugation 3 has a small lateral constriction marking the start of the node 5, the geometry of which is complex as explained above. Moreover, the bevel shape of the reinforcement portions 16 substantially corresponds to the inclination of this lateral constriction, and so the reinforcement portion 16 approaches the node 5 as closely as possible for optimum support of the corrugation.
Moreover, but not shown, the edge surface of the external wall 22 is also bevelled. Thus the edge surface of the external wall has a face inclined relative to the longitudinal axis of the reinforcement portion 16. This bevelled edge surface has a bevelled face facing toward the high corrugation 3. Thus if the first wave reinforcement 11 is moved in the longitudinal direction in the high corrugation in which it is accommodated, the contact between the reinforcement portion 16 and the high corrugation 3 occurs at the level of the bevelled edge surface the face of which espouses the shape of the high corrugation. This contact therefore occurs with no risk of degrading the high corrugation through cooperation between the bevelled edge surface and the high corrugation 3, there being no risk of the edge surface of the external wall 22 degrading the high corrugation 3.
The sole 15 has a width less than the width of the lateral constriction marking the beginning of the node 5. In other words, the distance separating the lateral walls 18 of the sole 15 is less than the width of the high corrugation 3 at the level of the lateral constriction marking the beginning of the node 5. Thus the projecting portion 24 of the sole 15 can be inserted in the node 5 as shown in
The projecting portion 24 of the first wave reinforcement 11 advantageously projects longitudinally in the node 5 in the direction of the fold 7 beyond the minimum height reduction of the high corrugation 3 formed by the concave portion 9. However, the distance separating the projecting portions 24 of two successive first wave reinforcements 11 is greater than the width of the adjacent second wave reinforcement 12 accommodated in the low corrugation 4 forming the node 5. In other words, the projecting portions 24 of the first wave reinforcements 11 are stopped prior to the low corrugation 4 so as not to be in line with said low corrugation 4. Thus as shown in
The connecting member 13 is accommodated in the soles 15 of the two successive first wave reinforcements 11 in such a manner as to assemble said successive first wave reinforcements 11.
The complementary shapes of the connecting member 13 and the housing 20 of two successive first wave reinforcements 11 enables the insertion of the connecting member 13 into the housings 20 with good cooperation between the connecting member 13 and the soles of said first wave reinforcements 11, thus ensuring good maintenance of the alignment of said first wave reinforcements 11.
For example, the connecting member 13 may be inserted in each housing 20 to a distance of 2 to 3 cm, or again, and preferably, a distance greater than 5 cm, notably 5 to 8 cm, in order to cooperate with the first wave reinforcements 11 over a length sufficient for stable maintenance of the alignment of said first wave reinforcements 11.
As shown in
A connecting member 13 in the form of a sleeve 25 can advantageously be slid into the sole 15, enabling manufacturing tolerances to be ignored, and to ensure by such more or less insertion of the sleeve 25 in the soles 15 to make good any manufacturing play. Thus the sleeve 25 of this kind has a central portion 27 and two ends 28 separated by said central portion 27. The central portion 27 corresponds to the distance separating the two soles 15 and the ends 28 are the portions of said sleeve 25 inserted in the soles 15. The relative sliding between the connecting member 13 and the first wave reinforcements 11 also makes it possible to absorb thermal contraction of the wave reinforcements without producing stresses.
A sleeve 25 of this kind may be produced in numerous ways and may be solid or hollow.
The abutment surfaces making it possible to limit the insertion of the connecting member 13 into the soles 15 could be produced in numerous ways. In an embodiment not shown, attached parts are fixed to an upper face of the plate 25 in order to form said abutment surfaces. Thus for example screws may be fixed to but not pass through the plate 25 in order to cause said plate 25 to project, the insertion of the plate 25 into the housings 20 being limited by abutment of the upper wall 19 of the soles on these screws. In another embodiment not shown rivets could fulfil the same function, such rivets preferably projecting only from the upper surface of the plate 25. In another embodiment not shown but derived from
The sole 15 includes a lower wall 17, two lateral walls 18 and an upper wall 19. The lower wall 17, the lateral walls 18 and the upper wall 19 conjointly define a hollow passage in the sole 15. The sole 15 further includes in said hollow passage reinforcing walls 21 connecting the lower wall 17 and the upper wall 19.
The reinforcement portion includes an external wall 22. This external wall has a shape complementary to the shape of the high corrugation 3 under which the first wave reinforcement is intended to be accommodated. The external wall 22 typically has two lateral walls 29 each forming a lateral face of the reinforcement portion 16. Each lateral wall 29 is developed from the sole 15, more particularly from an upper end of a respective lateral wall 18 of the sole 15, extending as far as a summit of the reinforcement portion 16. The external wall delimits with the upper wall 19 of the sole 15 a hollow passage in the reinforcement portion 16.
The reinforcement portion further includes an internal web 23. This internal web in the variant shown in
The junction between each first curved portion 30 and the upper wall 19 of the sole 15 is preferably made on an upper face of said upper wall 19 in line with the junction between a lower face of said upper wall 19 and a respective reinforcing web 21 of the sole 15.
In a variant shown in
In a variant not shown the reinforcement webs 32 of the first wave reinforcement 11 as shown in
The connecting member 13 shown in
In this variant, a plate 33 is fixed to the central portion 27 of the sleeve 25. This plate 33 is fixed in a manner such that it does not pass through the sleeve 25 in order not to cause the sleeve 25 to project in the direction of the thermal insulation barrier 2.
The plate 33 carries two lugs 34 each of which projects laterally from the sleeve 25. Each of the lugs 34 is accommodated in the hollow portion of a second wave reinforcement 12.
Each lug 34 is preferably elastic. In the embodiment shown in
In the embodiment shown in
To make
The second wave reinforcements fastened to the connecting member may be retained in numerous other ways. In an embodiment not shown the second wave reinforcements 12 include internal reinforcement webs as in
The embodiment shown in
During the assembly of the tank, rows of wave reinforcements 11, 12 are installed and retained in position on the thermal insulation barrier 2 before being covered by corrugated metal plates. These corrugated metal plates are of rectangular shape and carry high corrugations 3 and low corrugations 4. The edges of said corrugated metal plates intersect the high corrugations 3 and the low corrugations 4 between two successive nodes of said corrugations 3, 4. Thus wave reinforcements 11, 12 positioned under corrugations 3, 4 at the level of the edges of corrugated metal plates are conjointly covered by two successive corrugated metal plates.
In
Initially, as shown in
A first end 38 of these rows 37 of first wave reinforcements is moreover assembled by means of a connecting member 13 to the first wave reinforcements 11 partly covered by the metal plate already anchored to the insulating barrier. Thus this first end 38 of the rows 37 is retained in position on the thermal insulation barrier 2 by said metal plate already anchored to the thermal insulation barrier 2.
A second end 39 of these rows 37 of first wave reinforcements 11 opposite the first end 38 is retained in position on the thermal insulating barrier 2 by means of a fixing rail 40. This fixing rail 40 is temporarily fixed to the thermal insulation barrier 2 by any appropriate means, for example by means of screws, nails, etc. This fixing rail 40 is for example temporarily fixed to the metal inserts 35, said metal inserts including for example a threaded orifice enabling cooperation with the fixing screw of the metal layer 40. In another embodiment, the fixing rail 40 may be temporarily anchored to pins serving to anchor the thermal insulating barrier 2 or by means of a fixing lug sliding in the space between two insulating panels forming the thermal insulation barrier 2. This fixing rail 40 covers the first end 39 of each row 37 in order to retain in position on the thermal insulation barrier 2 said second end 39 of these rows 37.
The connecting members 13 and fixing the ends 38, 39 of the rows 37 of the first wave reinforcements 11 thus enable retention in position of said rows 37 on the thermal insulation barrier 2.
Secondly, as shown in
In the embodiment shown in
Thirdly, and finally, as shown in
As explained above, the edges of the corrugated metal plate 42 of this kind interrupt the high corrugations 3 between two nodes 5. Consequently, first wave half-reinforcements 43 are arranged at the level of the high corrugations 3 interrupted by the edges of the metal plate 42. In order to retain the first wave reinforcements 11, 43 in the high corrugation 3 of the metal plate 42, retaining clips 44 are arranged on the edges of said metal plate 42. These retaining clips 44 include a portion arranged on the internal face of the metal plate 42 and a portion accommodated in the reinforcement portion 16 of the first wave half-reinforcement 43, as shown in
In a similar manner to the first wave reinforcements 11, 43, the second wave reinforcements 12 are installed in the low corrugations 4 of the metal plate 42 and second wave half-reinforcements 45 are installed on the low corrugation portions interrupted at the level of the edges of the metal plate 42. The second wave reinforcements 12 and these second wave half-reinforcements 45 are retained in the low corrugations 4 by cooperation with the connecting members 13 between the first wave reinforcements 11 and retaining clips (not shown) similar to the retaining clips 44.
Thus the wave reinforcements 11, 12, 43, 45 are retained in position in the metal plate 42 and form a unitary assembly. This assembly is positioned on the thermal insulation barrier 2 and then, after positioning it, the retaining clips are removed to enable the fixing by welding of the metal plates 42 to the metal inserts 35 of the thermal insulation barrier.
This variant embodiment is distinguished from the variants described above in that the first wave reinforcements 11 accommodated under the longitudinal portions 6 of the high corrugations 3 do not have any projecting portion 24. Thus the sole 15 and the reinforcement portion 16 of the first wave reinforcements 11 conjointly form an end face 46 of the wave reinforcement 11. This end face 46 faces the node 5 in which the connecting member 13 is accommodated, the node 5 not being shown in
In a manner analogous to the embodiment described above with reference to
In this embodiment the projecting portion 24 is replaced by an attached spacer 47. This attached spacer 47 enables the bottom part of the high corrugation 3 to be supported like the projecting portion 24 described above. To this end, the attached spacer 47 has for example a structure analogous to the projecting portion 24, that is to say a structure analogous to the structure of the sole 15.
Thus as shown in
In an analogous manner to the connecting member 13 described above with reference to
The first lugs 28 of the connecting member 13 shown in
The attached spacers 47 enable limitation of the sliding of the first wave reinforcements 11 under the high corrugations 3. In particular these attached spacers immobilize the first wave reinforcements 44 in the direction of the node 5, thus preventing the end faces 46 of said first wave reinforcements 11 from coming into contact with the sealing membrane 1 at the level of the node 5. This absence of contact enables degradation of the sealing membrane 1 at the level of the nodes 5 to be prevented.
Furthermore, attached spacers 47 of this kind fulfil the role of abutments for immobilizing in position the first wave reinforcements 11 and guarantee correct positioning of said first wave reinforcements 11 on the thermally insulative barrier 2 during assembly of the sealing membrane 1 onto the thermally insulating barrier 2. This abutment function is particularly useful in the case of tank walls featuring a vertical component, preventing the first wave reinforcements 11 from being moved by the effect of gravity.
The attached spacers 47 may be fixed to the connecting member 13 as a preliminary manufacturing step. Thus connecting members 13 to which the attached spacers 47 have previously been fixed are positioned on the thermally insulative barrier 2 and the first wave reinforcements 11 are positioned on said thermally insulative barrier 2 by inserting into the sole 15 of said first wave reinforcements 11 the lug portions 28 projecting from the attached spacer 47.
In the context of a sealing membrane assembly as described above with reference to
For assembly of the final metal plate of the sealing membrane, the attached spacers 47 are typically mounted on but not fixed to the first lugs 28 of the corresponding connecting members 13. Said connecting members 13 are positioned on the thermally insulative barrier 2. The attached spacers are then slid along the first lugs 28 to enable the positioning of the first wave reinforcements 11 in such a manner as to adapt the position of said first wave reinforcements 11 to the construction constraints generated by the already installed portions of the sealing membrane 1. The attached spacers are then brought into contact with said first wave reinforcements 11 and fixed to the connecting member 13.
In this embodiment, the sole 15 of the wave half-reinforcements 43 is at least partially open on the lower face of said wave half-reinforcements 43. In other words, the sole 15 of these wave half-reinforcements 43 has an end opposite the connecting member 13 the lower wall 17 of which is not developed as far as the edge opposite said connecting member 13. Thus said wave half-reinforcements 43 form an open housing 59 in which is accommodated a connecting sleeve 60 intended to connect two adjacent wave half-reinforcements 43 belonging to two adjacent lattices 56. This open housing 59 is therefore delimited by the upper wall 19 and the reinforcement wall 21 of the sole 15 of the wave half-reinforcement 43. The connecting sleeve 60 has a shape complementary to the shape of the open housing 59, for example a parallelepipedal shape.
When a first lattice 56 is positioned on the thermally insulative barrier 2, a sleeve 60 is typically inserted into the open housing 59 and in each of the wave half-reinforcements 43 of said first lattice 56. When a second lattice 56 is attached to the thermally insulative barrier 2, the wave half-reinforcements 43 can be positioned directly by accommodating the sleeves 60 previously installed on the thermally insulative barrier 2 in the open housings 59 of the wave half-reinforcements 43 of that second lattice 56. Connecting sleeves 60 of this kind make it possible to ensure continuity of the wave reinforcements under the corrugations 3, 4.
Moreover, the open housing 59 can be longer than a connecting half-sleeve 60 so as to provide play for positioning the connecting sleeves 60 in the open housings 59. Such positioning plays make it possible to take up any assembly play of the metal plates of the sealing membrane, in particular when positioning the final metal plate of the sealing membrane 1.
Wave half-reinforcements 43, 45 of this kind assembled by connecting sleeves 60 moreover offer greater flexibility for possible repair of the sealing membrane and/or the wave reinforcements 11, 12, 43, 45, only the damaged portion having to be removed for the repair.
In a variant not shown only one of the two wave half-reinforcements 43 or 45 assembled by a connecting sleeve 60 includes the open housing 59, said connecting sleeve being slid into the other wave half-reinforcement of said pair.
In these variants shown in
Moreover, these first wave reinforcements 11 include two internal webs 23 as described above with reference to
The various variants described above may be combined with one another. Thus in an example shown in
As shown in this
In the variant illustrated in
The lateral portions 66 each have a lower face 67 facing the lower wall 17, said lower faces 67 conjointly delimiting with the lateral walls 18 and the lower wall 17 the housing 20 in which the end 28 or the lug 34 is accommodated. The housing 20 thus has a plane section extending parallel to the lower wall 17, that is to say having a width dimension greater than its thickness dimension, allowing cooperation with the end 28 or the lug 34 having a similar section and able to transmit the lateral stresses between the connecting member 13 and the wave reinforcement 11, 12. Thus, in the presence of asymmetrical stresses on either side of the node 5, such a connecting member 13 offers rigidity that solidly maintains the alignment between two successive wave reinforcements 11, 12 accommodated under a corrugation 3, 4 and assembled by said connecting member 13.
Furthermore, the wave reinforcement 11, 12 in this variant has two internal webs 23 as described above. Each internal web 23 is developed between a respective lateral portion 66 and the internal face of the reinforcement portion 22. More particularly, each internal web 23 is developed from one end 68 of a respective lateral portion 66, said end 68 being opposite the lateral wall 18 from which said lateral portion 66 is developed, in the direction of the internal face of the wall 22 of the opposite reinforcement portion 16, that is to say extending the lateral wall 18 opposite the lateral wall 18 from which said lateral portion 66 is developed. These two internal webs 23 cross substantially at the centre of the reinforcement portion 16.
In the embodiment illustrated in
The lower recesses 69 are developed in the thickness direction of the sole 15 and are recessed into the lower wall 17 at the junctions between the lower wall 17 and the lateral walls 18. Similarly, the upper recesses 82 are developed in the thickness direction of the sole 15 and are formed in the lateral portions 66 at the junctions between said lateral portions 66 and the lateral walls 18.
Such recesses 69, 82 make it possible to effect a precise fit, which is limited to the mounting plays between the end 28 or the lug 34 and the surfaces delimiting the housing 20. Thus, for example if the wave reinforcements 11, 12 are produced by extrusion or moulding, the junction zones between the lateral walls 18 and, on the one hand, the lower wall 17 and, on the other hand, the lateral portions 66 do not have a curved portion that can obstruct the housing 20 and interfere with the end 28 or the lug 34 during the insertion of said end 28 or lug 34 into the housing 20.
The embodiment illustrated in
In this variant embodiment, corrugations are developed perpendicularly to a ridge 83 formed between a first facet 84 of the tank wall and a second facet 85 of said tank wall. Furthermore, corrugations are developed parallel to said ridge 83. More particularly, in the example illustrated in
In this variant, a node 5 is thus formed in line with the ridge 83. Similarly, a high corrugation 3 is continuous between the first facet 84 and the second facet 85 of the wall.
In the embodiment illustrated in
Such a high corrugation 3 may, as explained above, be subject to asymmetrical stresses on either side of the node 5 covering the ridge 83. It is thus necessary to ensure the alignment of the wave reinforcements 11 situated on the two facets 84, 85 on either side of the node 5, that is to say to ensure that the wave reinforcement 11 situated on the first facet 84 and the wave reinforcement 11 situated on the second facet 85 preserve a longitudinal direction comprised in one and the same plane perpendicular to the ridge 83.
For this purpose, the connecting member 13 according to this variant embodiment differs from the connecting member described above with reference for example to
More particularly, the central portion 27 is plane and has a rectangular section. A first end 28 is developed from a first edge 86 of the central section 27 at an angle corresponding to half the angle between the two wall facets 84, 85. A second end 28 is developed from a second edge 87 of the central section 27, opposite the first edge 86, with an angle corresponding to half the angle between the two wall facets 84, 85. In other words, the ends 28 are each developed from the plane central portion 27 and have, between one another, an angle corresponding to the angle between the two wall facets 84, 85. Thus, the first end 28 is developed parallel to the first facet 84 and the second end 28 is developed parallel to the second facet 85. The first end 28 is inserted into the housing 20 formed by the hollow sole 15 of the wave reinforcement 11 situated in the longitudinal corrugation portion 6 forming the node 5 and situated in the first facet 84 and the second end 28 is inserted into the housing 20 formed by the hollow sole 15 of the wave reinforcement 11 situated under the longitudinal corrugation portion 6 forming the node 5 and situated in the second wall facet 85.
In an analogous manner to the ends 28 described above with reference to
The technique described above for producing a fluid-tight and thermally insulative tank may be used in reservoirs of different types, for example to constitute the primary sealing membrane of an LNG reservoir in a land installation or in a floating structure such as a methane tanker or other ship.
Referring to
In a manner known in itself, loading/offloading pipes 73 disposed on the top deck of the ship can be connected by means of appropriate connectors to a maritime or harbour terminal to transfer a cargo of LNG from or to the tank 71.
Pumps onboard the ship 70 and/or pumps equipping the land installation 77 and/or pumps equipping the loading and offloading station 75 are used to generate the pressure necessary to transfer the liquefied gas.
Although the invention has been described in connection with a plurality of particular embodiments, it is obvious that it is in no way limited to them and that it encompasses all technical equivalents and combinations of the means described within the scope of the invention.
Use of the verbs “include”, “comprise” and conjugated forms thereof do not exclude the presence of elements or other steps other than those stated in a claim.
In the claims, any reference sign in brackets should not be interpreted as a limitation of the claim.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1850874 | Feb 2018 | FR | national |
| 1852568 | Mar 2018 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2019/050232 | 2/1/2019 | WO | 00 |
