ES2277768B2 - WATERPROOF TANK AND THERMALLY ISOLATED WITH CALUXING ELEMENTS AND UXTAPUESTOS. - Google Patents

Abstract

Waterproof and thermally insulated tank with juxtaposed heating elements. Waterproof and thermally insulated tank constituted by tank walls fixed to the supporting structure (1) of a floating work, presenting the aforementioned tank walls, successively, in the sense of thickness, from the inside to the outside of said tank, a barrier primary watertight (8), a primary insulating barrier (6), a secondary watertight barrier (5) and a secondary insulating barrier (2), being essentially constituted, at least, one of the aforementioned insulating barriers by juxtaposed heating elements, including each heat-insulating element a thermal insulation filler (76) and supporting elements (75) that rise through the thickness of said thermal insulation filler to absorb compression stresses, characterized by the fact that the said carrying elements of an element They are made in the form of at least one supporting structure (70) formed in one piece that includes, each time, joining means that the aforementioned carrying elements are rigidly joined together.

Description

Waterproof and thermally insulated tank with juxtaposed heating elements.

The present invention relates to the realization of waterproof and thermally insulated tanks constituted by tank walls fixed to the supporting structure of a floating work, suitable for production, the storage, loading, transportation by sea and / or unloading of cold liquids, such as liquefied gases, especially with high methane content The present invention also relates to a methane vessel equipped with such a tank.

Transport by sea of liquefied gas at very low temperature is effected with an evaporation rate per day of navigation that is interested in reducing as much as possible, which implies that the thermal insulation of the tanks is improved corresponding.

A sealed tank has already been proposed and thermally insulated consisting of tank walls fixed to the supporting structure of a ship, presenting the aforementioned walls of tank, successively, in the sense of thickness from the inside towards the outside of said tank, a primary waterproof barrier, a primary insulating barrier, a secondary waterproof barrier and a secondary insulating barrier, being essentially constituted by less, one of the aforementioned insulating barriers by elements juxtaposed heaters, each heating element including a thermal insulation padding arranged in the form of a layer parallel to said tank wall and supporting elements that are lift through the thickness of said insulation filler thermal to absorb compression efforts.

For example, in document FR-A-2527544, these insulating barriers consist of closed parallelepiped plywood drawers filled with perlite. The drawer internally comprises parallel support braces interposed between a lid panel and a bottom panel to resist the hydrostatic pressure exerted by the liquid contained in the tank. Plastic foam non-bearing braces are placed between the support braces to ensure their relative positioning. The manufacture of such a drawer, including the assembly of the outer walls of plywood sheets and the placement of the struts, requires numerous assembly operations, especially stapling. In addition, the use of a powdery material, such as perlite, complicates the manufacture of the drawers, because the powdery material raises dust. Thus, to have a good sealing of the drawer against dust, it is necessary to use high quality plywood, therefore expensive, that is to say a plywood that does not contain knots. In addition, it is necessary to tamp the powdery material with a certain pressure in the drawer, and it is necessary to circulate nitrogen in each drawer to evacuate all the air present, for safety reasons. All these operations complicate manufacturing and increase the cost of drawers. On the other hand, if the thickness of the insulating drawers of an insulating barrier is increased, the risk of buckling of the walls of the drawers and the support braces increases considerably. If you want to increase the buckling resistance of the drawers and their internal support braces, you must increase the section of the mentioned braces, which increases both the thermal bridges established between the liquefied gas and the bearing structure of the vessel. In addition, if the thickness of the drawers is increased, it is found that very unfavorable gaseous convection currents are produced inside the drawers to obtain good insulation
thermal.

In the document FR-A-2798902, others have been described thermally insulating drawers intended for use in a tank of this type. Its manufacturing procedure consists of alternately stack a plurality of low foam layers density and a plurality of plywood plates, with interposition of glue between each foam layer and each plate, until the height of said stacking corresponds to the length of the aforementioned drawers, in slicing the aforementioned stacking in the sense of height at corresponding regular intervals to the thickness of a drawer, and to stick to one and another part of each stacked slice thus cut, a bottom panel and a panel plywood top, extending the aforementioned panels perpendicular to the aforementioned cut plates that serve as suspenders. Although a good compromise is obtained in terms of buckling and thermal insulation resistance, it should be noted that this manufacturing process also requires numerous assembly stages

US-4 416 715-A describes a composite rigid insulating panel by a folded sheet and a wrapped one. The envelope is filled with granular insulating material. The folded sheet constitutes the armor which stiffens the envelope. The folded sheet, in one piece, which It serves as an armor for the wrap, is made by folding a sheet of paper or cardboard The folded sheet, taken in isolation, does not present stiffness at the level of the folds formed, which constitute other So many flexible joints between the faces. For this reason, during the transfer of the sheet between two mounting positions, the folded sheet is kept in shape by projections and fingers.

The object of the invention is to propose a tank of this type, improving at least one of the characteristics between the cost price of the tank, the pressure resistance of the walls, and thermal insulation of the walls, without harming The other features. Another object of the invention is to propose a tank of this type whose heating elements are easier of manufacturing without harming the pressure resistance of walls and thermal insulation of the walls and, if possible, Improving these characteristics.

For this purpose, the invention aims at a waterproof and thermally insulated tank comprising at least one tank wall fixed to the hull of a floating work, presenting said tank wall, successively, in the sense of thickness, from the inside to the outside of said tank, a primary waterproof barrier, a primary insulating barrier, a secondary waterproof barrier and a secondary insulating barrier, being constituted, essentially, at least, one of the aforementioned insulating barriers, by juxtaposed heating elements, each heating element including an insulation filler thermal arrangement in the form of a layer parallel to said wall tank and supporting elements that rise through the thickness of said thermal insulation padding to absorb the compression efforts, characterized by the fact that the cited carrying elements of a heating element are made in the form of at least one bearing structure formed in one piece that includes, each time, joining means that join each other rigidly the aforementioned bearing elements and at least a height portion of the mentioned bearing elements.

A supporting structure of this type formed in a single piece gathers very advantageous mechanical properties, to the time, in terms of stiffness and buckling resistance in the thickness direction of the hollow elements, of ease of shaped, thermal insulation and cost price. Indeed, for a given geometry of the bearing elements, their resistance buckling is enhanced by rigid integral joints, with regarding separate bearing elements. In addition, the manufacture of the joints between the bearing elements and bearing elements, is say at least a portion of its height, in the form of a single piece allows to save certain assembly operations, allows the obtaining a relatively rigid bearing structure without excessively increase the section of the bearing elements and / or their thickness and therefore thermal bridges, and simplifies the placement of the thermal insulation filling inside the element heat insulating

According to a preferred embodiment of the joining means, said joining means of a bearing structure comprise a panel that extends parallel to said tank wall on one side of said heating element, the said bearing elements protruding with respect to an inner face of said panel. In others words, in this case, the supporting structure comprises a panel bottom or a cover panel of the heating element. By agreement, a panel called the side of the heating element is called a cover turned into the tank and a panel is called bottom located on the side of the heating element turned towards the bearing structure The bearing structure thus formed can also include a bottom panel and a panel of top.

According to an advantageous embodiment of the supporting structure, at least one cited supporting structure of a heating element has the shape of a hollow profile that It has a constant section according to the longitudinal direction.

For example, such bearing structures can Obtained by extrusion or pultrusion of any material suitable. Such constant section profiles can be obtained, especially, by means of a continuous extrusion row, to whose output is cut the hollow element to the desired length of so that the dimension of the corresponding heating elements It can be easily modified. Many forms of Profile section

The bearing elements may have a shape anyone. According to an advantageous embodiment of the carrying elements, the aforementioned carrying elements of a bearing structure includes at least two longitudinal partitions arranged at a distance from each other to define between them, at less, a constant section socket suitable for receiving the filling of thermal insulation. Such partitions serve both as braces supports to withstand the pressure exerted on the heating elements, such as separations between the alveoli. These alveoli, which can be in number of one, two, three or more per  heating element, allow easy insertion of the filling of insulation, especially through one end in the case of a profile.

Advantageously, said partitions Longitudinals include at least one septum noticeably perpendicular to said tank wall. A structure of this type improves the distribution of tensions in the partitions Longitudinal

Longitudinal alveoli may present, then, a section that is substantially rectangular or square.

Preferably, the said partitions Longitudinals include at least one inclined partition with with respect to said tank wall, having, advantageously, the less, two partitions inclined in opposite directions one respect of the other. Such inclined partitions allow to absorb both shear stresses, such as buckling efforts and twisting Thus, alveoli with other forms of section, for example trapezoidal or triangular.

Advantageously, said joining means of a bearing structure includes at least one junction wall that joins the aforementioned longitudinal partitions throughout their length, presented the aforementioned longitudinal partitions a thickening to level of its junction areas with at least one wall of Union. A connecting wall of this type can be parallel or inclined with respect to the tank wall. It can be treated, especially, a bottom panel and / or a cover panel. A Thickening of this type improves the strength and stiffness of the corresponding junction zone.

According to a particular embodiment of the longitudinal partitions, the heating element comprises a bottom panel and a cover panel and at least one of the partitions longitudinal outermost along a longitudinal direction side of the heating element is at a distance from the side edge corresponding of at least one of the aforementioned background panels and cover to delimit a terminal socket that has a side open side A terminal socket of this type, which may be provided on one or both sides of the heating elements, creates a space between the outermost longitudinal partitions of two adjacent heating elements. This space allows the insertion of an insulation padding to ensure continuity of the insulating barrier at the level of the interfaces between elements juxtaposed heaters.

According to another embodiment of the carrying elements, the carrying elements of at least one cited supporting structure include cross-section pillars small with respect to the dimensions of the heating element in a plane parallel to said tank wall.

Such small section pillars present the advantage of being able to be distributed in the heating element in Function of local needs. Adapting the number and the distribution of supporting pillars, element resistance Compressive heating can be done, especially, more uniform than with the prior art braces. It's possible, also, avoid a localized collapse or a pinch of a cover panel Such pillars may have a hollow section or solid and for which numerous forms are possible. In particular, hollow pillars of closed cross section allow to obtain a excellent buckling resistance, while minimizing Effective thermal conduction section.

According to another embodiment of the joining means, said joining means comprise arms that they extend between the mentioned carrying elements. Advantageously, said arms extend parallel to said wall of tank along at least one side of said filling of isolation. The arms, thus placed, offer a surface supplementary, which is added to the surface of the elements holders, for fixing an eventual bottom panel and / or lid formed independently of the supporting structure.

According to a particular embodiment of the supporting structure, at least one cited supporting structure It has the shape of a box with peripheral walls that they protrude all around the inner face of said panel. Such a conception allows the placement of a filling of insulation in the form of granular material. However, depending of the constitution of the insulation padding, can be used, also, heating elements devoid of walls peripherals

The heating elements can be opened or closed. Advantageously, the presence of a cover panel ensures a uniform support of the adjacent waterproof barrier. But nevertheless, such a panel is not mandatory because this support can be provided, also, sufficiently, by the own bearing elements Advantageously, the presence of a panel of fund ensures a well distributed transmission of the efforts of compression from the primary insulating barrier to the barrier secondary insulator or from the secondary insulating barrier towards the helmet. However, such a panel is not mandatory because this transmission can also ensure, sufficiently, by the supporting elements themselves. Such panels may be formed in several ways. So, as mentioned, a possibility is to form a supporting structure that integrates into a single piece a panel with the supporting elements.

In this case, according to a mode of particular embodiment of the heating element, this comprises a second panel formed independently of said structure bearing and that is fixed to the end of the mentioned elements supports opposite the first panel that forms the mentioned means of Union.

Any fixing means can be used For this end. Advantageously, the inner face of the second panel presents emptying arranged so that they cooperate for embedded with the supporting elements.

Preferably, in this case, the second panel It has a different thermal expansion coefficient than cited supporting elements so that, during commissioning cold of the tank, a tightening is carried out between said second panel and the mentioned bearing elements embedded in it.

According to an embodiment of the heating element, it has two supporting structures arranged so that their respective panels present the said inner faces turned towards each other, being the protruding bearing elements on said inner faces assembled two to two at the level of its ends located on the side opposite of the aforementioned panels, to form, each time, an element bearing of said heating element. In other words, in this case, the supporting elements of each of the two structures holders are placed end to end to form, each time, a bearing element that has two parts that extend, respectively, through a portion of the thickness of the element heat insulating Two structures can be used especially fully symmetrical carriers.

Advantageously, an insulation piece that It has a lower thermal conductivity than those mentioned bearing elements is interposed, each time, between the two assembled bearing elements. This allows to improve the thermal insulation provided by the heating element.

The assembly of the two supporting structures It can be done by any other means. Preferably, the bearing elements of the two bearing structures are assembled two by two, each time, by a connecting piece that It has a different thermal expansion coefficient than cited supporting elements so that, during commissioning cold of the tank, a tightening is made between the said piece of union and the mentioned carrying elements. In variant or in combination, the connecting piece can also be embedded, stuck, locked, etc.

Preferably, the structure or structures holders of a heating element are manufactured by a Molding, extrusion, pultrusion, thermoforming procedure, blowing, injection or rotational molding. The supporting structures can be made of any material suitable for the procedures above mentioned, especially plastic materials such as PC, PBT, PA, PVC, PE, PS, PU and other resins. Advantageously, the bearing structures are made of composite material. The use of this type of materials meets the conditions necessary to obtain supporting elements with a thickness smaller wall than with plywood, offering the same time a better thermal conductivity or of the same order of magnitude and a smaller expansion coefficient. For example, the mentioned bearing structures can be made of material Polymer resin based compound, for example resin polyester or other. In the sense of the invention, the materials Polymer resin based compounds include polymers or mixtures of polymers with all types of fillers, additives, reinforcements or fibers, for example glass fibers or others, which allow obtaining a stiffness and sufficient breaking strength and others properties. To decrease the density of the material and / or improve its  thermal properties, especially decreasing its conductivity thermal and / or its coefficient of expansion, can be used additives Similarly, a composite material can be used that include a large proportion of wood sawdust with a binder synthetic. In certain embodiments, the supporting structure it can also be laminated or plywood molded by hot compression.

According to an embodiment particular at least one said insulating barrier constituted by the aforementioned heating elements are covered, each time, by one of the aforementioned watertight barriers that is formed by courses of  thin sheet metal tables with low expansion coefficient whose edges are raised out of those mentioned heating elements, presenting the aforementioned elements Heat-resistant cover panels that carry parallel grooves, spaced across the width of a row of boards, in which they are retained welding brackets slidably, presenting each welding support a continuous wing protruding from the face outside the cover panel and whose two sides are welded so seal the raised edges of two rows of adjacent boards. The sliding welding brackets form sliding joints that allow different barriers to move from one to the other under the effect of thermal contraction differences and movements of the liquid contained in the tank.

Advantageously, said parallel grooves they are arranged in longitudinal ribs in projection in the cited cover panels. This embodiment allows reducing the thickness of the cover panels between the ribs. Advantageously, between said longitudinal ribs of the said cover panels are provided with a layer of insulating foam to support the sealing barrier that covers the elements gaps

Advantageously, secondary retention organs solidarity of the ship's supporting structure fix the elements heating elements that constitute the secondary insulating barrier against the aforementioned bearing structure and primary retention organs attached to the mentioned welding supports of the waterproof barrier secondary retain the aforementioned primary insulating barrier against the secondary waterproof barrier, retaining the mentioned supports of weld the said secondary waterproof barrier against the panels cover of the heat-insulating elements of the insulating barrier high school. Thus, an anchoring of the insulating barrier is performed primary in the secondary insulating barrier without damaging the continuity of the secondary waterproof barrier interposed between they.

According to an embodiment Preferably, said thermal insulation padding comprises rigid or flexible foam, reinforced or not, low density, is that is, less than 60 kg / m 3, for example of the order of 40 kg / m 3 to 50 kg / m 3, which represents very good thermal properties Thus, a material of order porosity of nanometer magnitude of airgel type. A airgel type material is a low density solid material that It has an extremely fine and very porous structure, which can Reach up to 99%. The pore size of these materials is typically extends between 10 and 20 nanometers. The structure nanometric of these materials significantly limits the mean free path of the gas molecules and therefore the convective transport of heat and mass. The aerogels are, then, very good thermal insulators, with thermal conductivity, for example, less than 20.10 <3> W.m <-1> .K <-1>, preferably less than 16.10 -3 W.m 1.K-1. These typically offer a thermal conductivity 2 to 4 times inferior to that of other classic insulators such as foams. The Aerogels can be packaged in different forms, for example, in powder form, of balls, of non-woven fibers, of fabric, etc. The excellent insulating properties of these materials allow to reduce the thickness of the insulating barriers in which are used, which implies a gain in useful volume in the tank.

The invention also provides a work floating, in particular a methane vessel, characterized by the fact that it comprises a tight and thermally insulated tank of according to the previous invention. Such a tank can especially used in a floating production facility and storage (known by the English acronym FPSO), which serves to store the liquefied gas for export from the production center, or in a floating storage unit and regasification (known with the English acronym FSRU), which serves to unload a methane vessel with a view to feeding a gas transport network.

The invention will be better understood, and others objects, details, features and advantages of it, will be put manifest more clearly in the course of the description which follows in a particular embodiment of the invention, given solely for illustrative and non-limiting purposes, referring to The attached drawings. In these drawings:

- Figure 1 is a perspective view debarking of a tank wall according to a mode of general embodiment useful for understanding the invention,

- Figures 2 and 3 represent an organ of primary retention of the tank wall of Figure 1, seen according to two perpendicular directions,

- Figure 4 is a cross-sectional view of a tank wall according to an embodiment of the invention,

- Figure 5 is a partial view in perspective of an insulated tank wall drawer represented in figure 4,

- Figure 6 is an enlarged view of the area XV of Figure 4,

- Figure 7 is a perspective view debarking of a tank wall area according to another embodiment of the invention,

- Figures 8 to 10 represent the section transverse of other embodiments of a heating element with a supporting structure in the form of a hollow profile,

- Figure 11 represents in perspective a bearing structure molded in one piece,

- Figure 11A is a partial sectional view representing a variant of the bearing structure of the figure eleven,

- Figure 12 is a perspective view in exploded view of two types of heat-resistant elements made with the help of the supporting structure of figure 11,

- Figure 13 is a partial sectional view that represents the assembly of a heating element of the figure 12,

- Figures 14 and 15 are analogous views of the Figure 11 representing other variants of the structure bearing

- Figure 16 is a partial sectional view of a heating element according to another embodiment of the invention,

- Figure 17 is a top view of the bearing structure of the heating element of Figure 16,

- Figures 18 to 21 represent other ways of realization of supporting elements in the form of pillars, seen in cross section,

- Figures 22 and 23 represent, in view from above and in section according to line XXIII-XXIII, a bearing structure of heating element according to another embodiment,

- Figure 24 represents in perspective a one-piece thermoformed bearing structure,

- Figure 25 is a perspective view, in exploded view of a heating element according to another embodiment, the insulation filling is omitted.

Several modes will be described below. of realization of a sealed and thermally insulated tank integrated and anchored in the double hull of a work of type FPSO or FSRU or a methane type vessel. The general structure of a tank of this type is itself well known and presents a way polyhedral The description will therefore be limited to only one tank wall area, being understood that all the walls of the Tank present a similar structure.

Referring to figures 1 to 3, it is described now a general embodiment useful for understanding the invention. In figure 1, an area of the double hull of the ship is seen designated by the figure 1. The tank wall is composed, successively, in its thickness, of a secondary insulating barrier 2 which consists of 3 drawers juxtaposed in the double hull 1 and anchored to it by secondary retention organs 4; a barrier secondary seal 5 supported by the drawers 3; a barrier primary insulator 6 formed by drawers 7 juxtaposed and anchored to the secondary waterproof barrier 5 by primary retention bodies 48 and, finally, by a primary waterproof barrier 8 supported by the drawers 7.

Drawers 3 and 7 are heating elements parallelepipedics that have an identical or different structure from one another and the same or different dimensions.

Secondary retention organs 4 are fixed to bolts 31 soldiers to double hull 1 according to a grill regular rectangular so that these retention organs 4 ensure, each time, the retention of four drawers 3 whose corners They get together. Two retention bodies are also provided. Secondary 4 in the central area of each drawer 3.

The secondary waterproof barrier 5 is made according to the known technique in the form of a membrane constituted by rows of Invar 40 boards with raised edges. As best seen in Figure 3, the cover panels 11 of the 3 drawers have longitudinal grooves, with section in the form of Inverted T, designated by the figure 41. A welding support 42, in the form of an Invar band folded in an L-shape, is inserted slidably in each slot 41. Each course of Tables 40 extends between two welding brackets 42 and presents two edges raised 43 soldiers, each time, continuously, by a welding bead 44 to the welding support 42 corresponding, as seen in figures 2 and 3.

Also, the anchoring of the drawers 7 of the primary insulating barrier is made, every time, in the four corners and at two points in the central area of drawer 7. For this, a primary retention body 48 is used each time which is represented in detail in figures 2 and 3. The retention body Primary 48 has a lower cap 49 integral with one leg 50 welded at several points 51, for example three, to a support of welding 42 above the raised edges 43 of the courses of tables 40. A stem 52 made of Permali, a composite material based on resin impregnated beech wood, it has one end lower fixed to lower bushing 49 and upper end fixed to a bushing 54 integral with a support washer 53 which it rests on the cover panels 11 of the drawers 7 staying in grinding 28 at the level of the corners of the drawers 7 and a level of central chimneys 30. Bushing 54 is threaded and screwed to a corresponding threaded end of the stem 52. When the washer 53 has thus been placed, they are introduced locking screws 56 through the perforations 55 made on washer 53 and screwed on panel 11 to prevent, thus, any subsequent rotation of the washer 53. At each barrier insulator, drawers 3 and 7 are juxtaposed with a small interleaved space of the order of 5 mm.

Advantageously, as insulation filler in drawers 3 and / or 7, a layer of nanoporous materials is included Airgel type, which are very good thermal insulators. The aerogels also have the advantage of being hydrophobic, so that is avoided, thus, to absorb the humidity of the ship in the barriers insulators An insulation layer can be made with aerogels, possibly bagged, in textile form or in the form of balls.

In general, aerogels can be made from various materials that comprise silica, aluminum, hafnium carbide, as well as varieties of polymers. In addition, according to the manufacturing procedure, the aerogels can be produced in powder form, of balls, of monolithic sheet and reinforced flexible fabric. The aerogels are manufacture, generally, extracting or displacing the liquid of a micronic structure gel. The gel is typically manufactured by transformation and chemical reaction of one or more precursors diluted This results in a gel structure in the that a solvent is present. To displace the solvent from the gel are usually used hypercritical fluids such as the CO2 or alcohol. The properties of aerogels can be modified by various dopants and reinforcing agents.

The use of aerogels as fillers of insulation allows to significantly reduce the thickness of the barriers primary and secondary insulators. They can be conceived, for example, barriers 2 and 6 of a thickness of 200 mm and 100 mm respectively, using a textile airgel mattress in drawers 3 and 7. The tank wall then has a total thickness of 310 mm In variant, a tank wall having 400 can be conceived mm total thickness using, each time, a layer of particles of airgel, especially airgel balls, in drawers 3 and 7.

Referring to figures 4 and 5, it will now describe a first embodiment of a tank waterproof and thermally insulated according to the invention. At first embodiment, the primary insulating barriers and Secondary are formed by profiled drawers monoblocks 70 filled with an insulating material, instead of drawers 3 and 7 before mentioned. A drawer 70 of this type is represented in perspective in figure 5. This is obtained by extrusion of a composite material based on a polymer resin and fibers, by example a polyester or an epoxy resin reinforced with fibers of glass or carbon For this, the material can be worked from the following way: first, the fibers of the resin in a static or pressure bath. These happen next to a row that has the function of giving the profile geometry correspondent. The polymerization takes place simultaneously. He product obtained is continuous and is trimmed to the dimensions adequate. It is, therefore, an online manufacturing continues, in which they are, from one end to the other, the fibers and resin, the row and the finished product to be Cut to dimensions.

The drawer 70 is presented in the form of a profile of constant section with a bottom panel 71 and a cover panel 72 parallel, rectangular and, between these panels, partitions longitudinal 75 that delimit a plurality of alveoli Longitudinal 73 of globally rectangular section, as well as two terminal pockets 74 at the level of two side edges of the drawer 70. Longitudinal partitions 75 thicken at the level of the zones terminals 68 connected to the bottom panel 71 and the cover panel 72. Alveoli 73 and 74 serve to receive an insulating filler 76, for example phenolic foam, low polyurethane foam density, eventually reinforced with fibers, and / or one or more layers of airgel based insulation material.

In the example depicted in Figure 5, the thickness of the bottom panel 71 is 6 mm, the thickness of the cover panel 72 is 9 mm and the thickness of the longitudinal partitions 75 is, each time, 6 mm. The number of longitudinal partitions 75 is an example purely illustrative and can be modified at will.

The bottom panel 71 presents, at the level of two alveoli 73, longitudinal notches 77 that pass through, each time, the entire thickness and the entire length of panel 71. You are notches 77 serve to pass the retention organs of the drawers 70. On the vertical of the two notches 77, the panel of cover 72 has two longitudinal grooves 78 of section in inverted T shape. Slots 78 have the same function as the slots 41 of the first embodiment. A stand of welding 42, in the form of an Invar band folded in an L-shape, is slidably inserted in each slot 78.

The drawers 70 of the secondary insulating barrier 2 and of the primary insulating barrier 6 are, each time, anchored in four points For this, the cover panel 72 has two perforations 80 surrounded each time by a grinding 81 and also arranged in the vertical of the two notches of the bottom panel 71.

Referring to figures 4 and 6, it is described now the realization of the tank wall according to the first embodiment. The drawers 70 that form the insulating barrier secondary 2 are anchored to double helmet 1, each time, by four bolts 82 welded to double hull 1 and arranged in front of the perforations 80, in which a washer is introduced each time 83 which rests on the bottom panel 71 and a nut 84. As the geometry of the double hull 1 is imperfect, coves of thickness around the threaded bolts 82. The thickness of each Thick cove is calculated by computer from a topographic survey of the inner surface of the double hull 1. Thus, the bottom panels 71 are positioned along a regular theoretical surface. Between the bottom panels 71 and the double helmet 1, are provided, in a classic way, round bars of polymerizable resin, not shown, which are glued to bottom panels 71 and smash against the double hull during the placement of the drawers 70 so as to ensure a support of these. To prevent this resin from adhering to the double hull, it is provided between these a sheet of kraft paper, not shown.

A cylindrical chimney 85 is available in the insulating padding 76 to be able to perform these operations from the top of drawer 70, fireplace that can be filled later With the insulating material.

In variant, the washer 83 may be arranged, also, so that it rests on the cover panel 72 instead of the bottom panel 71. For this, the washer 83 is fixed to the upper part of an elongated coupling member (by example, similar to organs 48) that is inserted through the chimney 85 and whose base is fixed to bolt 82, for example, by means of a filleted cap.

The watertight barriers 5 and 8 are made, as in the general embodiment, by the rows of boards from Invar 40 welded to welding brackets 42 housed in the slots 78 of the drawers 70. The welding brackets 42 of the Secondary waterproof barrier are introduced through the longitudinal notches 77 of the drawers 70 that form the primary insulating barrier 6. The anchoring of the drawers 70 which form the primary insulating barrier 6 is done with the help of primary retention organs 48 identical to those described in the general embodiment. Each time, the support washer 53 is lodges at the bottom of a grinding 81.

In the two insulating barriers, the drawers 70 they are juxtaposed edge to edge with minimal slack that allow to absorb alignment errors.

The forecast of perforations 80 in the vertical notch 77 ensures that the organs of retention 48 work well in the axial direction when they are attached to the underlying welding brackets 42. This allows, Also, use strictly identical drawers to make both insulating barriers, which simplifies its manufacture. But nevertheless, in the drawers of the secondary insulating barrier, the notches 77 could be replaced by cylindrical perforations.

The perforations 80 could be displaced, also, with respect to slots 78 in each of the barriers insulators

Referring to Figure 7, it is now described. a tank wall whose primary and secondary insulating barriers, 6, respectively 2, are formed by drawers 170a, respectively 170b, according to another embodiment.

In drawers 170a and 170b, the elements identical or analogous to those in drawer 70 carry the same figure of reference increased by 100 and these are only described in the to the extent that they are different. In figure 7 they are represented four drawers in service position.

An important feature of the drawers 170a and 170b is to present oblique longitudinal partitions 192 and 193, that is, not perpendicular to the bottom panels 171 and of lid 172. In the example shown, each drawer comprises a partition 192 inclined, approximately, 30º to 50º in one direction and a partition 193 inclined, approximately, 30º to 50º in the direction opposite. These partitions are provided, each time, in a socket longitudinal 173 near a terminal socket 174, so that It divides it into two alveoli of triangular section. However, they are other configurations possible in terms of number, position and to the inclination of the inclined partitions. Such partitions allow both shear stresses and buckling and twisting efforts applied to the drawer.

In drawers 170a and 170b, slots 178 intended to receive welding brackets 42 extend in the sense of width, that is, perpendicular to the longitudinal partitions 175. Bottom panel 171 of the drawers 170a and 170b does not, therefore, have longitudinal notches.

In drawer 170a, notches 177 for passage of the welding brackets 42 span the entire width of the drawer cutting the longitudinal partitions 175. In addition, you are notches 177 are offset with respect to slots 178. Thus, the coupling members 48 that retain the barrier 6 are they rest on the lid panel 172 at the level of the grinding 181 surrounding the perforations 180 that are displaced with respect to the slots 178. In Figure 7, it is planned to arrange at intervals regular nine coupling members 48 per drawer 170a. Without However, more or less than nine points of drawer anchor 170a and 170b, for example four or six, depending on the drawer size

The drawers 170b that form the insulating barrier secondary 2 are anchored to double helmet 1, each time, by four bolts 82 soldiers to double helmet 1 and that are introduced, each time, in a corresponding perforation of the bottom panel 171. In the vertical of these perforations (not shown) a step is foreseen cylindrical comprising holes 191 through the partitions oblique 192 or 193 and holes 190 through the lid panel 172. These holes allow to pass a socket wrench to tighten the nut 84. Alternatively, an organ of coupling through these holes to couple the bolt 82 to lid panel 172 rather than anchoring drawer 170b at the level of its  bottom panel 171.

The drawers 70 and 170a-b are self-supporting drawers that are able to withstand the pressure of the liquid inside the tank, so that the sealing barriers 5 and 8 supported by these have no need to support them themselves this pressure and, advantageously, are made in the form of very thin membranes, of a thickness, for example, of 0.7 mm of Invar

Figure 8 shows the section cross section of a 270 heat drawer that also has a profiled bearing structure. This bearing structure presents an inverted U-section with a lid panel 272 and two partitions 275 carriers substantially perpendicular to it. This one can manufactured by the procedure indicated above or by molding of plastic material. According to another possibility, this section in U can be obtained by forming a laminated wood panel or plywood An insulating material 276, for example foam low density plastic, fills the space between partitions 275 and is adhered to the profiled bearing structure.

In figure 10, a drawer has been shown heat exchanger 470 whose cross section has the shape of a Comb, with a lid panel 472 and supporting partitions perpendicular 475, which present, respectively, a thickening 468 at the level of the junction with panel 472. A material Insulator 476 fills the longitudinal alveoli formed between the 475 partitions. This comb structure can be extruded or milled in one piece. Another possibility is to set next to each other, for example by gluing or stapling, several drawers of the shape of the drawer 270.

The 270 or 470 drawer can be used instead of drawer 170a or 170b of Figure 7. In this case, the primary drawer rests on the secondary waterproof barrier 5 at the end of the 275 or 475 partitions. The secondary drawer rests in the same way on the resin rods mentioned above. To avoid a clamp of the barrier 5 or the round resin bars, an enlarged flat base can be provided at the end of each partition 275 or 475. A bottom panel may also be provided, not represented, fixed to the underside of drawer 270 or 470, by example by gluing, stapling and / or by recessing the ends of partitions 275 or 475 in the thickness of the panel. In the case in that such bases or a separate panel be added, drawer 270/470 can be used, of course, in an inverted position, that is, with panel 272/472 as background and bases, respectively, the panel separated, as a cover with slots that retain the supports of welding of the adjacent waterproof barrier.

A drawer is shown in figure 9 370, whose profiled bearing structure has a embrasures section, alternatively with lid panels 372 and bottom panels 371, which extend, each, in a portion of the width of the drawer and joined, each time, by supporting partitions 375. A layer of insulating material is formed by foam loaves Longitudinal 376a and 376b glued, each time, between two partitions 375, on panels 371, respectively, under panels 372. Drawer 370 may be used as shown or also with a cover panel and / or a supplementary bottom panel fixed to this one. Other sections of profiled bearing structure, for example in the form of H or of I.

Referring to figures 11 to 15, they are described other embodiments of heating elements or drawers usable to form the insulating barriers of the wall of tank whose general structure has been described in figures 1 to 3. Being the realization of the watertight barriers and the anchoring of the different barriers similar to the embodiments above, it will be useless to describe them again.

In figure 12, it is seen in perspective, in exploded view, a drawer 570 and a drawer 670 that are manufactured, respectively, with the help of molded bearing structures 500, of which a description will now be given referring to the figure 11.

The bearing structure 500 is a molded part by injection of any appropriate material. This presents a flat plate 571 with chamfered corners, for example in the form of 1.5 m square side or rectangle, on one of whose faces sixteen hollow circular cylindrical pillars stand out 575 arranged according to a regular square network, as well as two 581 tubes of smaller section at the level of a central area of the plate, as well as four triangular cylindrical pillars 580 at the level of the four corners of the plate. Plate 571 is continuous at the bottom level of pillars 575 and 580, but it is perforated at the bottom level by the tubes 581 to allow the passage of a coupler rod. By another part, for a drawer of the primary insulating barrier 6, the plate 571 is split to allow welding brackets 42 and the raised edges 43 of the barrier board runs secondary waterproof The 580 pillars serve to receive the support of the coupling elements used in each corner with the heating elements. The section of pillars 575 is, by example, 300 mm for a 1.5 m square plate. As filling insulating, bearing structure 500 may be covered by a low density foam layer that sneaks between, and within, the pillars 575.

The section of the pillars can be more or less great, being the important thing to always provide several pillars for drawer. Thus, the dimensions of the pillars, in section, can reach up to 1/3, or 1/2 of the corresponding dimensions of the drawer.

To form the drawer 570, a panel is fixed independent 572 of the same dimensions as plate 571 at end of pillars 575 opposite this plate. This panel can be fixed by any means (glued, stapled, embedded, etc...). In Fig. 12, circular grooves 573 are provided in the inside face of panel 572 to receive the end of each pillar 575 tightly.

The 500 structure and panel materials 572 can be chosen in such a way that a thermal zipping of 575 pillars in the panel. For example, with a 500 piece of PVC and a 572 plywood panel, which has a smaller thermal contraction, a tightening of the end of the 575 pillars on the circular core delimited by slot 573 during the cold setting of the tank. Conversely, a tightening of pillars 575 could also be obtained with a panel 572 that contracted more than piece 500.

Panel 572 has perforations 574 in front of the tubes 581 of the molded structure 500.

In drawer 670, two molded structures 500 identical are arranged symmetrically and assembled to each other putting their respective pillars 575 in support of each other. This assembly can be done by any means (gluing, welding, embedding, etc.) In Figure 12, it has been done with the help of a 680 union bushing that comes between each time between two pillars 575 alienated and that fits into these. This assembly is looks better in figure 13, which shows that the union bushing 680 features an outer ring 682 and an inner ring 681 attached by a radial tab 683. The pillars 575 fit between the two rings 681 and 682 and stop on each side of the tongue 683. The material of the 680 bushing can be chosen with a conductivity lower than that of pillars 575 to fulfill a function of thermal isolation. In variant or in combination, it can be chosen, also, with a coefficient of expansion that the pillars 575 to fulfill the function of thermal assembly. In variant, two grounded structures with section pillars complementary can be fixed to each other by engagement straight from the pillars to each other.

The 500 piece filled with foam can be used, also, alone, without supplementary panel, turning plate 571 towards the inside of the tank to support the adjacent waterproof barrier. The heating element thus formed rests through the 575 pillars in the watertight barrier or in the round bars of resin fixed to the helmet.

Figures 14 and 15 represent structures 600 and 700 molded carriers that allow elements to be made heaters similar to the structure 500 described previously.

In figure 14, the reference figures identical to those in figure 11 designate identical elements. The structure 600 comprises flat peripheral walls 601 which is extend continuously along four edges of the plate 571, so that they form a box suitable for containing a insulation material in powder form, ball or other. By example, a structure 600 containing airgel balls can be associated with a structure 600 that contains low foam density to form a 670 drawer as shown in the figure 12.

In Figure 15, flat plate 771 carries thirty-six hollow tubular pillars 775 of smaller section (per example, 100 mm) than the 575 pillars mentioned above, four pillars hollow tubular 780 of still lower section (for example, 50 mm to 60 mm) at the level of its corners and two tubular pillars 781 similar to the 780 pillars at the level of a central area of the plate 771 to pass coupling organs that serve the anchoring of the insulating barrier.

The structures 500, 600 and 700 can be injection molded. A similar structure can be obtained, also, by thermoforming from a material plate plastic. This possibility is illustrated in Figure 11A. In this case, the plate 571, initially flat, is heated and deformed from according to the footprint of a female mold 560. They are thus obtained bearing pillars 575 whose end on the side of the plate is open and whose opposite end is closed by a panel 583. In this case, the filling of the space 582 located inside the pillars 575, for example with foam, is made from the face of the 571 plate opposite these pillars.

The walls 601 can also be obtained by thermoforming:

Figure 24 represents in perspective a 1300 thermoformed bearing structure that includes a plate 1371, which can serve as a bottom panel or a drawer lid, and 1375 bearing pillars obtained similarly to the pillars 575 of Figure 11A. In the example shown, the pillars 1375 They have a truncated conical shape, which facilitates their forming. By For example, a pillar diameter that varies from 160 mm can be provided at the base 120 mm at the top at a height of, approximately 100 mm.

To serve as the bottom panel of a drawer of the primary insulating barrier, plate 1371 is provided with two 1384 longitudinal ribs that extend over the entire length of plate 1371. Each nerve 1384 is obtained during the thermoforming pushing the material in the same direction as the pillars 1375, so that an open V-fold is formed in the flat face of the plate 1371, whose interior space 1385 allows let weld brackets 42 and raised edges 43 of the secondary waterproof barrier. For the insulating barrier secondary, nerves 1384 are not necessary.

The structures have been described above. holders that include a plate to serve as a cover panel or background. Another embodiment of the element is now described. heating 870 referring to figure 16, in which the molded bearing structure 800 comprises supporting elements 875 Small section joined by 890 arms. This supporting structure is seen from above in figure 17. The supporting elements 875 are hollow circular cylindrical pillars arranged according to a regular net and joined by 890 arms that are arranged in shape of grid of square meshes. A cover panel 872 and a panel bottom 871, for example plywood, plastic, material compound or other material are glued to the two opposite faces of the supporting structure 800. The arms 890 are located in the end of the bearing elements 875 adjacent to panel 872 and they have a flat top face that can be used to glue the panel 872.

Figure 25 represents the heating element 870 in perspective, in exploded view, in one version slightly modified in terms of the arrangement of the arms of union 890.

Other arms may be provided at the level of lower end of the 875 pillars. The arms may be placed, also, at another level (for example at medium height) of the supporting pillars.

The interior space of drawer 870, namely the 880 interior space of the 875 pillars and the 876 space between the pillars, it is filled with one or several insulating materials. When low density foam is used, the drawer can be manufactured placing a rectangular structure 800 inside a mold  in view from above, pouring foam into the mold so that the structure 800 is immersed in a foam block parallelepipedic, and then fixing panels 872 and 871 to this block. Bottom panel 871 is not always necessary. One of the panels can also be molded in one piece with the 800 structure.

Although in the 500, 600 bearing structures, 700 and 800 have been described supporting pillars of circular section hollow, the supporting pillars can present any other sectional shape and any kind of spatial distribution, regular or not. For example, Figure 18 depicts a supporting pillar 975 constituted by a plurality of concentric cylindrical walls 976. On the pillar 1075 of Figure 19, the cylindrical walls 1076 have a square section. The pillars can have, also, a section variable in its height, for example pillars conical trunk

In figure 20, pillars have been represented 1175 distributed in alignment according to a regular table and that they have a hollow square section with chamfered corners. In Figure 21, pillars 1275, for example circular cylinders massifs, are distributed to the tresbolillo. They can be done, also, other sections, that is, rectangular, polygonal, in I, solid or hollow, in dihedral, etc ...

In all cases, such pillars can be molded in projection on a plate and / or be joined by arms and / or by any means of connection formed in a single piece with they. When low density foam is used as a layer of thermal insulation filling, it is particularly advantageous to strain this foam in a single stage over the entire surface of the plate of union, between, and eventually within, the supporting pillars. Another possibility is to machine wells in a formed foam block in advance and insert the bearing elements into the wells formed for this purpose.

In the case of a granular insulator, it is necessary use a heating element with peripheral walls, which, preferably, they are formed in one piece with the structure bearing, as in figure 14. Thanks to the shape of the elements small section carriers, the interior space of the box between these are not compartmentalized, so that the granular material is easier to spread across the entire surface of the element heat insulating Granular material can also be inserted in hollow pillars

Supporting pillars of very small section, by example less than 40 mm, they can remain empty without damaging the thermal isolation. Hollow pillars of small section may be also filled with a cone of flexible PE foam or wool glass.

Referring to figures 22 and 23, it is described now an embodiment of a heating element that comprises a 1470 monobloc hollow drawer made by rotational molding or by injection-blowing. This drawer is presented in shape of a hollow closed envelope 1477 that includes eight pillars 1475 truncated conical formed on the 1471 back wall of the envelope and that have, respectively, an upper wall 1483 suitable for leaning against the wall above 1472 of the wrapped to absorb compression efforts.

For fixing the drawer, six are planned 1480 frustoconical chimneys arranged on the periphery of the wrapped and open through the wall above 1472. You are chimneys have, respectively, a bottom wall suitable for lean against the 1471 back wall to absorb stress compression and capable of being punctured to receive a stem of fixation, schematically represented in 1431, which, for example, it is a bolt welded to the hull or a coupler attached to a barrier underlying seal.

The interior space 1476 of the drawer and the space 1482 interior of the 1475 pillars can be filled with any suitable insulating material, for example, by injection of foam.

Also, 1480 fireplaces can be filled of insulating material, for example PE foam or glass wool, after fixing the drawer.

To mold the 1470 drawer can be used, by example, high density PE, polycarbonate, PBT or other plastic. Fireplaces 1480 can be suppressed, too, if used another method of anchoring the drawers, for example couplers that pass between the drawers that must be anchored and that rely on the wall above 1472 in the manner of retaining bodies 48 of Figures 2 and 3. Bottom and / or cover panels can be fixed, also, to the walls of the envelope to reinforce it.

In the supporting structures 500, 600, 700, 800, 1300 and 1470 described above, the pillars can be replaced, also, by partitions that create compartments in the interior of the supporting structure.

Although heating elements have been described essentially parallelepipeds of right angles, are possible other section shapes, especially any polygonal shape apt to form a discretization of a plane.

Naturally, the insulation padding of a Heat element can comprise several layers of material.

When one of the primary insulating barriers and Secondary is done with the help of the heating elements described above, it is possible, but not necessary, to perform identically the other insulating barrier. In both barriers they can Use heating elements of two different types. One of the  barriers may be constituted by heating elements of the prior art

The anchoring of the insulating barrier drawers secondary and primary insulating barrier to the hull of the ship it can be done differently from the example represented in the figures, for example, with the help of retention organs fixed to the bottom panel of the drawers.

In a known manner, the angled joint of the primary and secondary insulating barriers, in the areas where the pillars of the bearing structure are angularly joined, can be carried out in the form of a connecting ring, the structure of which remains substantially constant throughout of the intersection edge of the walls of the supporting structure. The structure of such a connecting ring is well known and will not be described in detail. In the case of a tank integrated in a ship, such a ring is generally arranged along the angle formed between a longitudinal wall of the double ship hull and a
transverse partition to the ship.

In the sense of the invention, the expression Tank wall includes angled joint areas, especially, the union rings, whatever their forms, in which the heating elements described above  They can also be used.

Although the invention has been described in relationship with several particular embodiments, it is evident that is not limited in any way to these, and that includes all the technical equivalents of the means described, as well as their combinations if these fall within the scope of the invention.

Claims (10)

1. Waterproof and thermally insulated tank comprising, at least, a tank wall fixed to the hull (1) of a floating work, presenting said tank wall, successively, in the sense of thickness, from the inside to the outside of the said tank, a primary waterproof barrier (8), a primary insulating barrier (6), a secondary waterproof barrier (5) and a secondary insulating barrier (2), essentially consisting of at least one of the aforementioned insulating barriers, by heat-absorbing elements (3, 7) juxtaposed, each heat-insulating element including a thermal insulation filler (76, 276, 376a-b, 476) arranged in the form of a layer parallel to said tank wall and supporting elements (75, 175 , 192, 193, 275, 375, 475, 575, 775, 875, 975, 1075, 1175, 1275, 1375, 1475) that rise through the thickness of said thermal insulation padding to absorb compression stresses, being made the mentioned elements carrying an element Heat-insulating in the form of at least one supporting structure (70, 170a, 170b, 270, 370, 470, 500, 600, 700, 800, 1300, 1477) formed by a single piece that includes joining means (272, 371 , 372, 472, 571, 771, 890, 1371, 1471) that rigidly join said support elements together and at least a part of the height of said support elements, presenting at least one said bearing structure of an element heat-resistant (70, 170a-b, 270, 370, 470) the shape of a hollow profile that has a constant section according to a longitudinal direction characterized in that said means of attachment of the supporting structure comprise a panel (272, 371, 372, 472, 571, 771, 1371, 1471) extending parallel to said tank wall on one side of said heating element, said bearing elements protruding with respect to an inner face of said panel. 2. Tank according to claim 1, characterized in that said heat-insulating element (570) comprises a second panel (572) formed independently of said bearing structure (500) and which is fixed to the end of said elements supports (575) opposite the first panel (571) forming said joining means. 3. A tightly insulated and thermally insulated tank according to claim 2, characterized in that the inner face of said second panel has recesses (573) arranged so that they cooperate by recessing with said carrier elements (575). 4. A sealed and thermally insulated tank according to claim 3, characterized in that said second panel (572) has a different thermal expansion coefficient than said bearing elements (575) so that, during the setting on cold of the tank, a tightening is carried out between said second panel and said bearing elements embedded in it. 5. A sealed and thermally insulated tank according to claim 1, characterized in that said heat-insulating element (670) has two supporting structures (500) arranged so that their respective panels have said interior faces turned towards each other. another, the supporting elements (575) being projecting on said inner faces assembled two to two at the level of their ends located on the opposite side of said panels to form, each time, a bearing element of said heat-insulating element. 6. A tightly insulated and thermally insulated tank according to claim 5, characterized in that an insulating piece (680) is interposed between the two assembled bearing elements, which has a lower thermal conductivity than said bearing elements. . 7. Waterproof and thermally insulated tank according to claims 5 or 6, characterized in that the supporting elements of the two supporting structures are assembled two by two, each time, by a connecting piece (680) which has a coefficient of thermal expansion different from the mentioned bearing elements so that, during the cold setting of the tank, a tightening is carried out between said connecting piece and said bearing elements (575). 8. Waterproof and thermally insulated tank according to the preceding claims, characterized in that at least one said bearing structure (70, 170a-b, 270, 370, 470, 500, 600, 700, 800, 1300 , 1477) of a heating element is manufactured by a forming process chosen in the group comprising the molding, extrusion, pultrusion, thermoforming, blowing, injection and rotational molding processes. 9. Waterproof and thermally insulated tank according to the preceding claims, characterized in that at least one said insulating barrier (2, 6) constituted by said heat-resistant elements (70, 170a-b, 870) is covered by one of the aforementioned watertight barriers (5, 8) which is formed by spins of metal boards (40) of thin sheet of small expansion coefficient whose edges are raised towards the outside of said heat-insulating elements, the said heat-insulating elements presenting panels of cover (72, 172, 872) that have parallel grooves (78, 178) spaced across the width of a row of boards, in which the welding brackets (42) are slidably retained, each welding bracket having a continuous wing protruding from the outer face of the cover panel and whose two faces are welded tightly the raised edges (43) of two rows of adjacent boards. 10. Waterproof and thermally insulated tank according to claim 9, characterized in that secondary retention elements (82-84) integral with the ship's bearing structure fix the heating elements that constitute the secondary insulating barrier (2) against said bearing structure (1) and primary retention elements (48) attached to said welding supports (42) of the secondary waterproof barrier (5) retain said primary insulating barrier against the secondary waterproof barrier, retaining the said supports of weld the aforementioned secondary waterproof barrier against the cover panels of the heating elements of the secondary insulating barrier.