RU2379577C2 - Cellular tanks for storing of flow mediums at low temperatures - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: tank contains external plates, forming its top, side and bottom walls, and inner cellular construction, herewith all cells of this construction intercommunicates to each other on level of bottom wall of tank. At least part of external plates allows multilayer structure, and inner cellular construction is formed as self-balancing system of load perception and/or fixation of external plates. External lamellar layer of multilayer structure is fixed to inner cellular construction system either directly by means of fasteners, or through fittings or inner stiffening elements, with ability of transferring of stretching forces from side walls of tank to inner cellular construction system by means of anchoring or fasteners. Invention also relates to cellular construction for usage in tank for storing of flow mediums.

EFFECT: increasing of durability, volumetric efficiency and improvement of resistance against fatigue.

21 cl

Description

Technical field

The present invention relates to a tank (reservoir) for storing a fluid (fluid), preferably fluids (fluids) at low temperatures, to a sandwich multilayer structure for use in a tank and to a method for manufacturing a tank.

State of the art

There is a need to store liquefied natural gas (LNG) at a cryogenic temperature and at a pressure close to atmospheric at all stages of LNG production and delivery:

a) in stationary and floating production facilities (gas liquefaction plants);

b) at land enterprises for the production and storage;

c) during transportation on ships;

d) at stationary and floating receiving terminals, possibly equipped with regasification equipment;

e) at ground receiving terminals and installations for regasification.

Offshore production facilities and receiving terminals correspond to new areas in the LNG production and delivery chain, and several projects and concepts are being studied in this area. Tanks at floating production facilities and at receiving terminals will be used at different filling speeds, and this may be a problem for some tank systems. Due to the movement of the structure due to the action of waves, waves and dynamic movement of the fluid will occur in the partially filled tank, which will lead to high dynamic pressures on the tank structure. This important effect, called splashing, can pose a design problem for most existing tank concepts.

For offshore production facilities, the shape of the tanks is an important factor, since they will usually be located inside some structure, while the production equipment will be located on deck, i.e. over the tanks. Prismatic tanks are preferred because they allow the best use of the volume allocated to them. Another aspect important for offshore production facilities is the technology of manufacturing and installing tanks. Prefabricated tanks, which can be transported to the installation site as a single part or as a small number of components, reduce the total time and, therefore, cost. In addition, in relation to a fully manufactured tank, it is possible to conduct a leak test prior to installation. Membrane tank systems have a complex structure, and they must be assembled at the installation site, inside the finished structure, so the construction of such systems usually takes 12 months or more.

With regard to transportation on surface vessels, two main tank systems dominate the market: the Moss spherical tank system and the membrane tank systems developed by GTT (Gaz Transport et Technigaz, France). The freestanding SPB tank developed by IHI (Ishikawajima-Harima Heavy Industries Co., Ltd., Japan) is another possible system. The maximum capacity of vessels for the transportation of LNG currently produced is 138,000-145,000 m ³ , while the market already requires vessels with a capacity of 200,000-250000 m ³ . Vessels of this size can be a problem for existing tank systems. One of the main design problems associated with existing systems is the long construction period. A typical construction time for a ship containing 145,000 m ³ LNG is 20 months or more, with tank systems manufacturing and testing being the main bottlenecks. New difficulties for tank systems arise due to the planned offshore filling and emptying, which require the development of tanks designed for partial filling and the associated dynamic pressure during splashing.

The Moss spherical tank concept was originally developed in 1969-1972. using aluminum as a cryogenic material. The design is an autonomous tank with a partial secondary barrier. Thermal insulation is usually a foam placed on the outer wall of the tank. For ships and offshore structures, the concept of a spherical tank is characterized by a relatively low degree of use of a limited volume; however, it is not designed for the possibility of using a flat deck at offshore structures.

The development of membrane tank systems was begun in 1962; Then they were improved by Technigaz. Modern systems consist of a thin first membrane, a layer of thermal insulation from plywood boxes filled with perlite or foam, a second membrane from Invar steel or triplex, and, finally, a second layer of thermal insulation. Stainless steel membranes are made corrugated in order to take into account thermal contraction and expansion of the membrane, while Invar-steel membranes do not require corrugation. Structurally, the system is quite complex, it requires many special components and a large amount of welding work. Membrane welding and the presence of corrugations leads to an uneven concentration of stresses and to the variability of stresses due to splashing. This increases the likelihood of cracking due to fatigue and leads to a potentially high risk of leaks. Liquid splashing in partially filled tanks as a result of ship movements under the influence of waves imposes restrictions on such tanks: as a rule, during sea transportation, filling in the range of 10-80% is not allowed. Splashing usually leads to very high dynamic pressures on the inner walls of the tank, especially in the corner zones, which can lead to damage to the membrane and the thermal insulation in contact with it. Another difficulty is the inability to inspect the second membrane.

The SPB tank developed by IHI is an autonomous prismatic tank with a partial secondary barrier, made in the form of a traditional frame and cladding system, reinforced in the orthogonal direction. The system includes an external cladding and a reinforcement system consisting of stiffeners, frames, beams, stringers and bulkheads, similar to those used on a vessel of traditional design. Due to the presence of the listed structural elements, splashing is not considered a problem. Fatigue can be a problem for this tank system, due to the large number of parts and the concentration of local stresses. Thermal insulation is fixed on the outer surface of the tank, and the tank rests on a support system in the form of wooden blocks.

Mobil Oil Corporation developed a box-shaped tank design in the form of a polyhedron for storing LNG on land or on structures with ground bases. This design is described in international application PCT / US 99/22431. The tank is formed by a rigid frame with truss ties, on which a shell is attached to hold the stored liquid gas inside the tank. An internal frame with truss ties ensures that the entire internal volume of the tank is connected in order to give the tank the ability to withstand dynamic loads caused by the splashing of stored fluid as a result of short-term disturbances caused by seismic activity. Prefabricated sections of the tank are assembled at the installation site. The design of the tank consists of a large number of parts, so it is necessary to take into account the influence of stress concentration on its service life, limited by fatigue.

Cylindrical tanks dominated in the market of ground receiving terminals and regasification units are designed as tanks with single protection or with full (double) protection. The single-shielded tank contains an inner tank and an outer container. The inner tank is made of cryogenic material, usually steel with 9% Ni content. As a rule, it has a cylindrical wall with a flat bottom. For the manufacture of internal tanks, prestressed concrete and aluminum were also used. The outer container is usually made of carbon steel. Its sole purpose is to keep the insulation in the required position, and it does not provide significant protection in case of destruction of the internal tank.

Most LNG storage tanks built in recent years around the world are designed as tanks with double (full) protection. In such designs, the outer tank is designed to preserve the entire contents of the inner tank in case of destruction of the latter. In tanks of this type, the external tank (or wall) is usually constructed in the form of a wall of prestressed concrete at a distance of 1-2 m from the internal tank with placement of heat-insulating material in the inter-wall space. Land-based LNG tanks of a traditional design are expensive, their construction period is approximately 1 year, and they should be built in areas with developed local infrastructure.

Disclosure of invention

The main purpose of the present invention is the creation of a new type of high-performance autonomous low-temperature tanks, which can be in the form of a hexagon or prism and which are fully capable of completion. In other words, the tank can be expanded to any size using the principle of a substantially repeating structure. The problem solved by the invention is also the creation of a tank capable of withstanding a large number of pressure and temperature cycles during its service life.

Another objective is to create a tank with high volumetric efficiency. In other words, the volume of the tank should fill the surrounding spaces (such as ship holds, storage sections on floating platforms, segmented areas in land factories, etc.) as much as possible, which are usually structured in the form of hexagons, parallelepipeds or other prisms.

An additional task is to create a tank system that solves the problem of splashing internal fluid for tanks on board a vessel or on floating installations.

Another task is to create a thermally insulated autonomous tank, which can, in whole or in part, be manufactured in advance, and then transported and installed in a predetermined position in a given place.

The next task is to create a low temperature tank that has improved functional properties in terms of improved fatigue resistance, service life and ease of inspection.

A further task is to create a tank system that, in economic and technical terms, is able to compete with existing systems of a similar purpose.

The purpose of the present invention is also to create an autonomous system that has the structure of a tank or cell and can be made in one place and then delivered to another place (for example, on board a vessel, to a floating terminal or to some land section) and installed in this second place.

The tank can be equipped with all necessary equipment to perform its functions, including filling or emptying systems, monitoring systems, etc.

These problems are solved thanks to the creation of the invention described in the attached claims.

The invention relates to a tank in the form of a prism or hexagon, i.e. to the storage system of fluids (fluids) at very low temperatures. The outer reservoir contains lateral, lower and upper walls, and at least part of these walls contains a structure formed of plates, which at the same time is a structural element and serves to prevent leaks. In one embodiment, this design may also provide, in whole or in part, the required thermal insulation of the tank. The slabs forming the indicated structure contain a sandwich-type multilayer structure. In the context of the invention, the term “sandwich” refers to the presence of two layers connected or connected to each other by means of a core with load transfer between the layers. A particular embodiment of such a core structure between two layers comprises an outer layer having a plurality of through cavities overlapped by the membrane material.

The design of the external plates that make up the walls is fixed using a self-balancing system of walls (usually thin) forming an internal cellular structure. This design effectively fixes the outer walls in the presence of static and dynamic loads to which they are exposed.

In a preferred embodiment, the layered structure of the plates is a sandwich multilayer structure, which contains at least two surface sheet layers of metal or material with similar properties and a core located between these layers. The core can be a continuous layer of material or a structure containing partitions of various profiles, forming a cell structure between two sheet layers, mainly oriented parallel to the sheet layers. This internal structure may be a honeycomb or similar structure located between the sheet layers. The main thing is the ability of the core "sandwich" to transfer loads between its sheet layers. Additional insulation may also be provided outside and / or inside the multilayer structure. The advantage of using such a multilayer structure with two sheet layers and a core is also the possibility of installing gas detection means between the two sheet layers.

A tank may take the form of various prisms, however its typical geometry corresponds to a hexagon or a box shape. The outer side walls (side plates) and the lower wall (lower plate) are subject to static and dynamic fluid pressures and are accordingly designed to withstand such loads. A metal sheet or plate in the form of a multilayer structure provides the necessary bending strength relative to the core, which may be a structure or material intended mainly for the transmission of shear forces.

The core of the multilayer structure may form part of the thermal insulation of the tank, for example, through the use of a material with very low thermal conductivity, comprising at least part of the material or structure of the core. Sufficient strength and rigidity of the outer plate can also be ensured by using additional stiffening elements.

The outer walls are effectively fixed on the vertical lines of interface with the walls of the internal cellular structure and should, in essence, transfer loads as a result of the action of the plates on these supports. Similarly, the bottom plate may comprise a multilayer structure, preferably of a sandwich type, which is subjected to fluid pressure and weight. The slab corresponding to the bottom wall essentially transfers these loads to suitably positioned support means, for example, to the nodal points of the wall system forming the internal cellular structure. These support means, which allow relative thermal displacement relative to the foundation, will be described later.

The walls of the internal cellular structure can be made prestressed in its plane in the horizontal direction, taking into account the pressure forces transmitted from the outer walls. For tanks located on land, the walls of the internal cellular structure can be very thin sheets, the dimensions of which are selected in accordance with the principle of "fully stressed construction". Very thin sheets can cause difficulties in their use; a way to overcome such difficulties will be discussed later. With regard to tanks on moving bases, the walls of the internal cellular structure must be designed taking into account dynamic loads from the side of the stored fluid.

In relation to a multilayer structure, the core material in the outer plates of the tank has the dual function of providing partial thermal insulation and structural rigidity; To perform this function, it must have sufficient strength and thickness. In one embodiment, the core of the multilayer structure may comprise the bulk of the thermal insulation.

In one embodiment, in which the core is in the form of a continuous layer of material, various types of materials can be used as the core, provided that they have acceptable properties with respect to stiffness, strength, thermal conductivity and coefficient of thermal expansion (compression). In a typical case, a mixture of materials consisting of fine-grained components and components with larger granules embedded in the matrix material can be used. The fine-grained components may be different types of sand or various inorganic and organic materials. Larger components are typically porous grains that provide strength and thermal insulation with low weight. Such aggregates may be cellular glass, fired expanded clay, or other variants of fossil raw materials, or organic materials such as plastics. Examples of aggregate materials commercially available are Perlite, Liaver, Liapor and Leca. An alternative to the use of light aggregates is the introduction of a matrix into the material before introducing the binder of air or gas bubbles.

As the binder or matrix material, one or more typical binder materials can be used, such as cement paste, silica, polymers or any other material that is effective in this context. Special chemical components can also be added to the paste (dough) in order to provide special properties, such as desired viscosity, low shrinkage or volume control, the required cure rate, fatigue characteristics, etc. To achieve higher strength, especially tensile strength, metallic, inorganic or organic fibers can also be introduced into the mixture.

As already mentioned, the core-forming layer may be a structure formed by partitions between two sheet layers to obtain cells of various shapes between the sheet layers. These cells will be oriented in the longitudinal direction, mainly parallel to the planes of the sheets. In this case, there may be partitions oriented mainly transversely to the planes of the sheets or forming an angle with them other than 90 °, or forming a structure close to cellular.

There are several methods for producing a multilayer structure in the outer plates of a tank in accordance with a preferred embodiment of the invention. The core material in the form of a continuous layer of material can be directly introduced in a fluid state into the space between the sheet layers that perform the form function for filling the core material. Alternatively, the core material may be prepared as a semi-finished product in the form of sheets or blocks that are introduced in the form of a thick suspension or adhered to the sheet layers and to each other. The core in its thickness may also consist of various layers of glued sheet material. Moreover, for the manufacture of various sheets can be used in various materials.

In another embodiment, the multilayer structure can be extruded as an integral structure having both sheet layers and a core, or only an element can be extruded that forms a core and can be welded to the sheets of the multilayer structure. The core forming member may also be formed of several separate elements welded to each other to form a single core member.

In another embodiment of the invention, the core material and its dimensions are mainly chosen to provide the required structural strength, while the necessary additional thermal insulation is provided mainly by a thermal insulation layer that is not part of the multilayer structure and is located outside with respect to it. In this case, the core of the multilayer structure can be made of a material with relatively high strength, such as high-quality concrete or a metal structure. For a core in the form of a continuous layer, for example, high-strength concrete with a compressive strength of 80 MPa and a density of 2400 kg / m ³ can serve as a material. In this case, additional external thermal insulation is not exposed to significant efforts, which allows the use of inexpensive thermal insulation materials, such as mineral wool or glass wool. Moreover, that part of the external thermal barrier that is part of the multilayer structure will be at an almost uniform temperature corresponding to the temperature of the fluid inside the tank. Therefore, that part of the wall that is formed by the multilayer structure will contract or expand in a substantially uniform manner. The main part of the temperature gradient will fall on the insulating layer located outside, however, this layer will not experience problems due to thermal deformation of the multilayer structure located on the inside of this layer, since it is formed by a non-rigid, unstructured material.

The inner layer of the multilayer structure of the outer plates of the tank is usually made of metal having sufficient strength and resistance to thermal and chemical influences from the side of the fluid stored in the tank. This layer can also be formed by non-metallic materials having similar properties. For a LNG storage tank, suitable materials may include steels containing 9% nickel or austenitic stainless steels, such as grades 3.04, 304L, 316, 316L, 321 or 347. Other metals may be used, including aluminum alloys or Invar steel. as well as composites. The outer layer is usually not exposed to such severe thermal and chemical influences as the inner layer. Therefore, it can be made, for example, from simpler grades of carbon structural steel. For both the inner and outer layers, there is also a requirement that the material must be suitable for bonding, for example by welding, and have good bonding ability to the core, regardless of whether it is a structure or a continuous material, or a set of blocks.

In the case of the use of core material with high strength, but low heat-insulating properties, the outer layer of the multilayer structure will be almost at the same thermal regime as the inner layer. In this case, an alloy capable of providing sufficient strength at a particular temperature condition should be applied to the outer layer.

The multilayer structure used in the plates may contain stiffeners to improve the bond between the elements of the multilayer structure, as well as to increase its structural strength. In one embodiment, if the core material gives the multilayer structure low structural strength, the required strength can be achieved using stiffeners. The stiffeners can be given a different shape, however, it is preferable that they have the form of plates with a width equal to the distance between the surface sheets and a length oriented in the direction from the bottom wall to the upper edge of the tank and preferably corresponding to the full height of the tank. Alternatively, the stiffeners may form a lattice structure. The gaps between the elements of this design can be filled with a continuous layer of material. Alternatively, empty spaces may be left so that the core structure in the multilayer structure will be formed by a lattice structure. A special case may be an outer wall made of plates with increased stiffness or having a box-like structure, i.e. not containing a multilayer structure.

The main components of the tank are the outer plates, which form the side, lower and upper walls and are thermally insulated multilayer plates, and the set of walls of the internal cellular structure, which, in essence, are self-balancing supporting or fixing walls for the outer plates.

The anchor walls of the inner cells, which form the inner cellular structure, must satisfy the same requirements as the inner sheet layer described above, i.e. typically they will be made of the same material. These walls can be made in several different ways. They can be flat sheets that fit together to form cells; alternatively, the honeycomb structure may be formed by corrugated sheets.

Another preferred option is to form a mesh structure using multiple beam elements extending from one side wall to the opposite wall. The cellular structure is constructed by laying the beam elements transverse to the previous beam element, so that the third beam element will be laid parallel to the first beam element and transverse to the second element, and the fourth beam element transverse to the third element. As a result, a lattice structure will be formed with gaps between the beam elements located one above the other, i.e. between the first and third or third and fifth elements, etc. or between the second and fourth, fourth and sixth elements, etc. In other words, it can be said that the beam elements form something like a “log cabin” with gaps between different logs of this design. Preferably, the beam elements extend from one outer wall of the tank to its opposite outer wall.

The honeycomb structure according to this embodiment is such that in the plane A transverse to the side walls, the longitudinal axes of all the beams A lie in plane A essentially parallel to one another. All beams located directly above these first beams A lie in the second plane B, the longitudinal axes of these beams being essentially mutually parallel. The planes A and B alternate, forming the ABABAWAB sequence, until the desired height of the mesh structure is reached. Other designs are possible, for example, using a third layer of beams.

The angle between the beams of the first and second layers is preferably close to 90 °, which corresponds to cells of a rectangular or square shape. However, other configurations are possible in which the crossing beams form, in particular, angles of 60 ° / 120 °.

The contact points at which the beams of one layer are crossed with the beams of another layer, preferably lie on one straight line and form a zone for transferring the load, for example, from the upper wall to the lower wall of the tank.

The beams used in this construction can have different cross-sectional profiles. So, their profile can be T-shaped, I-shaped, rectangular or round. The lateral protrusions provided by the beams of a T-shaped or I-shaped profile provide an additional effect in preventing damage caused by splashing by creating turbulence in the fluid flow resulting from the movement of the tank. In addition, these protrusions on the beams reinforce the cellular structure, providing an increase in the contact areas between the layers of beams in the multilayer beam structure, and also more rigidly set the position of the contact area between the various layers of beams. Although the listed profiles are standard for beams, other configurations of cross sections are possible, providing the same effect of fixing (anchoring) the side walls, minimizing the effects of splashing, and at the same time, the formation of bonds between different structural cells.

To increase the strength and facilitate the manufacture of the docking zone, the walls of the inner cells may contain a separate component to which the wall segments are attached. Such a solution can be used both for walls of flat sheets and for walls in the form of a beam structure described above. This component may be, for example, a vertical beam of circular or rectangular cross-section. Since the walls of the inner cells themselves will be very thin (only a few millimeters thick), especially when using walls in the form of flat sheets, in applications in which dynamic movement takes place, it may be necessary to increase the strength of the walls in the transverse direction. The required increase can be achieved using stiffeners mounted on one or both sides of the wall, or, alternatively, by performing horizontal corrugations on a thin sheet of the inner wall. It should also be noted that the aforementioned tubular component in the joint zone of the segments of the inner wall will have to essentially bear the weight of the cell walls, because these walls practically have no bearing capacity in the vertical direction, since, being very thin, they tend to warp. The specified tubular component will also have to absorb the weight of the upper wall of the tank.

The splashing phenomenon is highly dependent on the area of the free surface area of the fluid volume, and this zone according to the invention is segmented into smaller zones using the system of walls of the inner cells. For example, the problem of splashing in most cases can be practically eliminated by using internal cells with an area of 5-10 m ² . In this case, the walls of the inner cells will be subjected to moderate dynamic loads and should be subject to this circumstance, for example, have corrugations on the beams that give the beams the required bending and shear strength. Similarly, the slabs that make up the outer walls and which are preferably in the form of multilayer structures are designed to take into account the stresses of the fluid, which may also include moderate components due to splashing. A specific feature of the present invention is that when using it, the severity of the splashing problem is less dependent on the degree of filling of the tank; in fact, as the degree of filling decreases, the total values of the fluid pressure will decrease.

Despite the fact that the internal volume is divided into separate cells, in the case of using walls of flat sheets in the lower part of the walls of the cells there will be holes with which the fluid level in the cells is equalized and convenient access is provided for maintenance personnel to all cells for inspection purposes and repair. If the walls of the cells have a beam structure, then the connection between the cells is ensured by holes (gaps) between the beams forming the walls. If necessary, openings can be provided near the bottom wall for access by maintenance personnel. An important factor in this is that all the cells forming the cellular structure communicate with each other. The holes located at the bottom wall may be provided with reinforcing components located at their edges.

The grid formed by the walls of the inner cells can be subjected to stresses completely and evenly, so that in the case of using flat walls, their thickness can be very small (several millimeters); if a beam structure is used, these walls will have a low weight. This circumstance is important because the sheet material for the inner walls often must be high-quality expensive alloys that can withstand low temperatures and the chemical effects of the fluid in the tank. As already mentioned, the use of very thin sheets in the formation of the walls of the cellular structure can lead to a problem of insufficient rigidity. Therefore, in one embodiment, the wall of the cellular structure is provided with end elements on their opposite sides, which are joined with similar sides in the mating zone of the cellular structure. These end elements together form a reinforcing component, providing increased rigidity of the cell walls, as well as the cellular structure of the tank as a whole. In the case of the beam structure of the cell walls, the beams are preferably provided with protrusions to increase their rigidity.

These features allow you to practically implement the manufacture and assembly of the cellular structure. The multilayer design of the outer plates, as well as the use of the side, upper and lower walls as both structural components and elements involved in providing thermal insulation, are very effective in economic terms. In addition, both the inside and the outside of the tank are fully modular and repeatable. It follows that the manufacture of the tank can be automated to a very high degree. This, in turn, will contribute to strong economic performance.

In one embodiment of the invention, the corners of the outer walls may be rounded. One of the reasons for using rounded corners is that in this case the concentration of structural stresses can be reduced. Another reason may be some reduction in thermal stress between the two sides of the outer walls.

The method of manufacturing the tank is of great importance both for practical reasons and for ensuring the overall economic effect. The pre-fabrication of modules or the tank as a whole means a reduction in the production time, as well as the fact that the production of the tank can take place in parallel with the construction of the rest of the vessel, platform or platform on which the tank must ultimately be installed. A tank with a cellular system allows for the preliminary manufacturing and automation of the production process to a very high degree. All segments of the walls of the inner cells are essentially the same and can be manufactured in mass ("conveyor") production. Their attachment to joint reinforcing components can also be done in the same way and automatically. In some cases, the possibility of using highly efficient welding technologies, such as friction welding, laser or plasma welding, may be considered. In addition, the outer plates can be made of segments with the subsequent connection of the segments to each other and to the walls of the inner cells.

The described tank according to the invention will be suitable for storage of various fluids and effective functioning in the temperature range from + 200 ° C to -200 ° C, and it is especially effective in relation to LNG. In addition, the tank will be able to withstand some excess of a given static pressure inside the tank. It can be placed on a floating facility or on land.

The tank can be mounted on a support system, which should provide one anchor point and means to prevent the tank from turning. Alternatively, the tank can be mounted directly on a sand foundation or on another foundation with similar properties.

Brief Description of the Drawings

The invention will now be explained by way of example of preferred embodiments given with reference to the accompanying drawings.

Figure 1 shows a tank according to one embodiment of the invention with the upper and one of the side walls removed.

Figure 2 presents the second variant of the tank according to the invention.

Figure 3 presents the third version of the tank according to the invention.

On figa and 4B shows a portion of the angle of the tank of figure 1 with, respectively, the first and second variants of the design of the walls of the inner cells.

FIG. 5A shows a detail of a tank corresponding to a third embodiment of an internal cellular wall structure attached to an outer plate.

On figv-5E presents examples of parts of the attachment to the outer plate of the walls of the inner cells corresponding to the second embodiment.

In FIG. 6A is a sectional view of one embodiment of a cell wall corresponding to a first embodiment of a mesh structure.

On figv shows in cross section the mating zone of the four cell walls according to the variant of figa.

On figa presents in cross section another embodiment of the cell wall corresponding to the first embodiment of the cellular structure.

On figv shows in cross section the mating zone of the four cell walls according to the variant of figa.

On figa-8D shows in cross section various embodiments of the outer plate of the tank according to the invention.

On figa-9B shown in perspective image of various embodiments of the corners of the outer walls of the tank according to the invention.

On figa-10B presents two perspective images of the tank according to the invention with the removed outer layer and the core of the multilayer structure.

11 shows a tank equipped with external stiffeners according to the invention with the side and top walls removed.

In Fig.12 shows a part of the tank of Fig.11.

The implementation of the invention

The tank 1 according to the invention contains side, upper and lower walls in the form of external plates, as well as an internal cellular wall structure. Figure 1 shows the three sides of the tank with three side plates 2, a lower plate 4 and an internal cellular wall structure 5, dividing the inner space of the tank 1 into cells of smaller volume. It is possible to use several different designs that form the side walls, the upper wall and the lower wall, as well as their mating zones. All such designs may have similar or different designs. In this case, the internal cellular wall structure can be formed in various ways. Various options for such designs and their elements will be discussed later.

The walls 20 of the inner cells forming the inner cellular wall structure 5 are in the form of sheets with a smooth surface. Holes 6 are made in them (possibly with edges provided with random beams) at the level of the bottom plate 4 so that all cells communicate with each other. At the same time, in relation to a large tank, it is possible to transfer personnel from cell to cell for the purpose of inspection and repair. The tank will also contain an unimagined filling and emptying system, as well as detection and monitoring systems and auxiliary equipment.

Figure 2 presents another variant of the tank 1 with side walls 2 and with an internal mesh structure 5 containing the walls of 20 cells. In this embodiment, the outer walls of the four corner cells are rounded, while in the embodiment of FIG. 1, these walls are only partially rounded, i.e. each of them has flat parts. Figure 3 shows an alternative embodiment of the tank 1, also having side walls 2 and an internal cellular structure 5 of the walls of 20 cells. In this embodiment, all side walls form right angles to each other.

FIG. 4A is a perspective view showing a portion of the tank of FIG. 1 corresponding to an embodiment in which the outer plates 2 have a multilayer structure (sandwich structure) consisting of an outer layer 8 and an inner layer 9, between which core material 10 is located. The multilayer structure also includes stiffening elements 11. These stiffeners can have several different shapes, and they preferably extend from the surface of one layer to the surface of another layer of the multilayer structure. In a preferred embodiment, the stiffeners are in the form of plates, the width of which is essentially equal to the distance between the surfaces of the layers of the multilayer structure, and the length is oriented in the vertical direction (along the side wall) and preferably corresponds to the full height of this wall. In FIG. 4A, the internal cellular wall structure is the same as in the first embodiment of FIG. 1, i.e. the cell walls are single flat walls 20 attached to one another in the zones 21 of their interface. The plates forming the inner walls 20 are preferably fixed to the side wall, in that place where stiffening elements 11 extend inside the multilayer wall structure. The fastening is carried out, for example, by welding the plate forming the wall 20 to the inner surface of the layer 9 of the multilayer structure. This solution is effective in relation to the transfer of loads between the outer walls and the design of the inner walls. A set of through holes (not shown in any of the figures) may be formed in the wall plates 20.

On figv presents a second variant of the internal cellular wall structure. In this embodiment, the cell walls 20 are formed by a plurality of beam elements (beams) 28 mounted one above the other to form the cell wall 20. A group of beams 28A forms a first layer of beams 28, and a second group of beams 28B is mounted above the beams 28A of the first layer so that their longitudinal axes are perpendicular to the beams of the first layer. Beams 28A in the third layer are arranged substantially parallel to the beams of the first layer. As a result, a lattice structure of several layers is formed in which the longitudinal axes of the beams of different layers have different orientations. The cell wall 20, thus formed, will have gaps between adjacent elements forming the wall 20. This solution provides the required communication between the cells, while creating the necessary obstruction for splashing in the tank mounted on the moving vessel. In the zone 21 of the mating walls 20 of the cells of the beam 28A, 28B are superimposed one on top of the other, thereby providing support for each layer of beams, and also forming the point of transfer of subsequent loads from the upper wall to the lower wall of the tank.

Beams 28A, 28B may be flat plates or may have a T-shaped, I-shaped or H-shaped section. By using the listed or other profiles with transverse protrusions at the ends or rectangular (including rounded rectangular) profiles in cross section, a more stable internal cellular wall structure is provided, since a beam of one layer can abut against its protrusions on the protrusions of the beam of the next layer. In addition, the beams can be welded or mechanically attached to one another to form an even more stable internal cellular wall structure. A beam element of this design can extend from one outer wall to another outer wall, so that each beam element is involved in the formation of the walls of several cells.

Thus, the cell walls 20 can be smooth flat elements (in the embodiment of FIG. 4A), flat elements with stiffeners (not shown), a plurality of beam elements or even sheets with corrugation elements 23, as shown in FIG. 5A. Such corrugation elements 23 can be oriented mainly in the horizontal direction. In this case, the internal cellular structure is formed by walls 20, which have mating zones 21. Preferably, in these zones 21 there is at least one reinforcing component 24. This component may be wholly or partially in the form of a pipe (with a round or square cross section) or consist of separate elements located at right angles to each other and abutting against lateral surfaces of two adjacent cell walls, as shown in FIG. 5A. Such reinforcing components can be installed in one corner or in all corners.

In accordance with the invention, the internal honeycomb structure is mounted on the outer walls of the tank, and this can be done in various ways. One of them is shown in figa, on which the walls of the 20 cells are attached to the inner surface of the multilayer structure at the locations of the stiffeners. This allows for the transfer of loads through the multilayer structure to its outer layer 8. Another possibility is shown in FIG. 5A, where a fastener 14 is mounted in the multilayer structure, the presence of which also allows you to transfer loads to the outer part of the multilayer structure in the outer walls. Another possibility is to weld the walls of 20 cells to the inner surface of the multilayer structure (this option is not shown).

Other options that are specially adapted to the design of the walls of the cells containing the beam elements are shown in FIGS. 5B-5E, moreover, the solutions presented are applicable for joining the walls formed by smooth or corrugated sheets.

On figv shows that the beam elements 28A are attached to the connecting parts 40 'in the form of a bracket, which is mounted on the outer wall 2 and protrudes into the cavity of the tank in the transverse direction relative to the outer wall. The connecting part 40 'is provided with a more protruding part mating with the beam element 28A and a less protruding part located between the beam elements 28A.

On figs-5E shows the cell wall formed by several beam elements 28A, which are attached to the outer side wall 2, consisting of two elements 2A and 2B, connected by a connecting part 40. The connecting part 40 in the form of a bracket, shown in figs -5E is provided with essentially U-shaped grooves for introducing into each of them an element of the outer wall 2.

A protrusion 45 is also formed on the connecting part 40, extending from it into the tank cavity in the transverse direction relative to the outer wall 2. The inner cellular wall structure 5 can be attached by means of beam elements 28A to the protrusion 45 in various ways. One attachment option shown in FIG. 5C corresponds to welding the beam elements 28A to the protrusion 45. Another embodiment is shown in FIG. 5D, where the beam elements 28A are attached to the protrusion 45 using a fastener 41 provided with two U-shaped grooves for insertion into one of them is a part of the beam element 28A, and the other part of the protrusion 45. The fastener is connected to the named parts by bolts drawn through the through holes 42. In the embodiment of FIG. 5E, the beam elements are provided with a U-groove for introducing the protrusion 45 ( what does compound exists a third embodiment) and are attached thereto, for example by welding.

6A-6B and 7A-7B show two different embodiments of the cell wall 20 provided with end elements 25, 25 ′ that interact with other end elements 25, 25 ′ to form a reinforcing component 24 in the mating zones present in the inner mesh constructions.

On figa wall 20 of the cell is presented in cross section. An end element 25, 25 'is attached to each of its ends, which has an elongated L-shaped profile in cross section.

The end elements 25, 25 'are attached to the wall 20 at points on the long (in FIG. 6A vertical) branch 26 of the L-shaped profile, while its short (in FIG. 6A horizontal) branch 27 is directed from the cell wall 20. As can be seen from figa, the short branches 27, 27 'of the two end elements 25, 25' are preferably located on opposite sides of the cell wall 20.

On figv in cross section shows the mating zone of the four walls 20, made in the embodiment shown in figa. The end elements 25, 25 'of the L-shaped profile with a long branch 26, 26' and a short branch 27, 27 'of all four walls 20 joined in the mating zone interact with each other to form a combined reinforcing component 24. In this case, the long branch 26 one end element 25 is attached to the short branch 27 of the other end element 25, and all four end elements together form a component with a rectangular section. The connection of the L-shaped end elements can be carried out by welding, screws, bolts, rivets or similar means.

On figa-7B shows another variant of the docking, and on figa presents the wall 20 'of the cell, at each end of which is fixed the end element 25' of a V-shaped profile.

On figv in cross section shows the joining zone of four walls 20 ', similar to the wall shown in figa. Four end elements 25 'form a reinforcing component 24' in the mating zone.

The outer plates of tank 1 forming the upper wall, side walls and lower wall according to the invention are preferably multilayer structures comprising an outer sheet layer 8 and an inner sheet layer 9 with a core located between them, which, as shown in Fig. 8A, can represent constitute a continuous layer of material or consist of structural elements, as shown in figv-8C. The core, at least partially, provides the strength of the outer wall and the thermal insulation of the tank. The multilayer structure may contain a set of structural elements (stiffeners) 11 located between the outer and inner sheet layers 8, 9, respectively. These elements can have various shapes, shown in figa-8C. So, on figa they are direct transverse stiffeners, on figv they form with sheet layers 8, 9 an angle other than 90 °. In the embodiment of FIG. 8C, these stiffeners and sheets forming the layers 8, 9 are made by extrusion as a single component. Of course, between the set of stiffeners there may be a continuous layer of material, as shown in figa.

In another embodiment shown in FIG. 8D, the multilayer structure may further comprise external stiffeners 12 protruding outward from the side, upper or lower plates, and an external thermal insulation layer 13. External stiffening elements 12 can pass through the outer thermal insulation layer 13 partially (as shown in FIG. 8D) or completely. As shown in FIG. 8D, there may be a connection between the walls 20 of the internal mesh structure 5, the stiffeners 11 within the multilayer structure, and the external stiffeners 12. Alternatively, the stiffening elements 11 and the external stiffening elements 12 may be extensions of the walls 20 of the cells. The stiffeners can be provided with cutouts, recesses or other elements that contribute to the reduction of heat transfer between the stiffeners.

On figa-9B presents examples of solutions to the design of the angles in which the outer walls are connected to each other 2. According to the solution of figa used corner 16, equipped with essentially U-shaped grooves to enter into them segments of the outer walls that are welded to the corner 16. According to the solution of FIG. 9B, the outer sheets of the multilayer structure of the outer walls 2 are directly connected to each other by welding to form a right angle.

On figa and 10B presents a perspective image of a tank according to the invention with the removed outer layer and the core of the multilayer structure in order to show the inner sheet layer 9 and plate elements 11 stiffness, forming partitions in the upper and lower walls 3, 4 and passing along the side walls 2 from the lower wall 4 to the upper wall 3. At both ends and in the joining zones of the stiffening elements 11 located on the lower wall 4, support means 30 are provided. These support means will be discussed later.

11 shows a tank according to the invention with the side and top walls removed, and FIG. 12 shows a part of the tank of FIG. 11. The side walls 2 in this embodiment comprise external stiffening elements 12 that form a grid and are oriented essentially in the vertical and horizontal directions. It can be seen that the wall 20 of the inner cellular structure 5 is attached to the side walls 2 at the locations of the external stiffeners 12, which improves the structural integrity of the tank. Provided that the system of stiffeners has sufficient strength, this option does not require structural rigidity in the insulation layer.

In one embodiment of the invention, the outer slabs may be connected to (and supported by other, existing and adjacent systems) at one or more points or in linear contact zones by means of elastic couplings, linear or non-linear mechanical devices, or pneumatic or hydraulic devices , or combinations of these devices. This solution is not presented in any of the figures. One of its specific options is to use the previously described support means in order to provide support for the side wall of the tank. However, as indicated above, many other options are possible. The beam structure forming the cell walls can be implemented using closed profiles with a round or rectangular cross section.

The invention has been described in detail above with the example of its various variants. However, numerous changes and modifications of these options may be proposed without departing from the scope of the invention defined in the attached claims. In particular, the design of the cells may have a different geometry. The outer structure can be supported in the transverse direction by structures surrounding it, for example, ship structures. Several layers of thermal insulation with different properties can be used, and these properties can vary for different plates forming the tank. Supporting means may be provided to support the tank in the transverse direction. Alternatively, for example, external structures such as a ship’s hull can be used as external support structures.

Claims (21)

1. A tank (1) for storing a fluid at particularly low temperatures, including support means for supporting the tank, allowing the tank to expand and contract as a result of temperature changes, and further comprising a multilayer structure comprising an inner sheet layer (9) and an outer sheet layer ( 8), forming at least part of the upper wall (3), side walls (2) and the lower wall (4) of the tank and connected with the internal cellular structural system (5) located inside the tank, characterized in that the multilayer jet the structure is fixed by the internal cellular structural system (5), and all the cells of this structural system communicate with each other under direct self-balancing tensile stress due to the pressure of the fluid acting on the opposing inner sheet layers (9), and the outer sheet layer (8) of the multilayer structure is attached to the internal cellular structural system (5) either directly by means of fastening means, or through connecting parts (40, 40 ') or internal elements (11) of a rigid and to transmit tensile forces from the side walls (2) of the tank to the internal cell constructive system (5) using anchoring or fastening means. 2. The tank (1) according to claim 1, in which the inner sheet layer (9) and the outer sheet layer (8) of the multilayer structure are connected to the inner cellular structural system (5) using anchor or fastening means. 3. The tank (1) according to claim 1, in which the multilayer structure contains a core located between the inner sheet layer (9) and the outer sheet layer (8), forming a multilayer structure, and configured to transfer load between the inner sheet layer (9 ) and the outer sheet layer (8). 4. The tank (1) according to claim 3, in which the core contains at least one stiffening element (11) extending between the inner sheet layer (9) and the outer sheet layer (8). 5. The tank (1) according to claim 4, in which the stiffening element (11) is attached to the internal cellular structural system (5) with the possibility of transmitting stiffness through the specified element (11), when using the tank (1), loads between the outer sheet layer (8) and the inner sheet layer (9). 6. The tank (1) according to claim 5, in which the anchor or fastening means of the internal cellular structural system (5) are located adjacent to the corresponding stiffeners (11, 12) installed inside the multilayer structure or connected with it, providing during use load transfer tank between the multilayer structure and the internal cellular structural system (5) through anchor or fastening means and a stiffener (11). 7. The tank (1) according to claim 1, in which the anchor or fastening means comprise a part (40, 41) in the form of a bracket connecting the internal cellular structural system (5) with a multilayer structure. 8. The tank (1) according to claim 1, in which the internal cellular structural system (5) contains walls formed by beam elements (28A, 28B), layer-by-layer superimposed on each other in a crossed configuration with the formation of a lattice, and beam elements in one layer have one orientation, and the beam elements in the next layer have a different orientation, with the formation of holes between the beam elements. 9. The tank (1) according to claim 1, in which the walls of the internal cellular structural system (5) are formed by flat elements. 10. The tank (1) according to claim 1, in which the internal cellular structural system (5) contains at least one zone (21) of the interface between the elements forming the internal cellular structural system (5). 11. The tank (1) according to claim 10, in which each mating zone (21) is located along the entire height of the internal cellular structural system (5) and is configured to bear the weight of the walls of the internal cellular structural system and the upper wall (3) of the tank. 12. The tank (1) according to claim 10, in which each interface zone (21) comprises at least one reinforcing component (24), which is installed with abutment in the lateral surfaces of two adjacent walls of the internal cellular structural system. 13. The tank (1) according to claim 12, in which the reinforcing component is formed by interacting end elements (25, 26, 27) attached to the ends of at least some of the walls of the internal cellular structural system that are joined in the interface zone. 14. The tank (1) according to claim 1, in which the multilayer structure comprises separate fastening or connecting elements (40, 41) for attaching the multilayer structure to the internal cellular structural system (5). 15. The tank (1) according to claim 1, in which the multilayer structure comprises an outer layer of thermal insulation superimposed on the outer surface of the outer sheet layer (8). 16. The tank (1) according to any one of the preceding paragraphs, in which the multilayer structure is attached to other existing adjacent structural systems and supported by them at one or more points or in linear contact zones by means of elastic ties, linear or non-linear mechanical devices, or pneumatic or hydraulic devices, or a combination of these connections and devices. 17. An internal cellular structural system (5) for hardening and maintaining a tank based on a multilayer structure containing upper, side, and lower walls and designed to store fluids, especially at very low temperatures, containing beam elements (28A, 28B) operating on stretching, covering the distance between the opposite walls of the tank (1) and made with the possibility of attaching to the walls (2) of the tank (1), characterized in that said beam elements (28A, 28B) are installed with mutual displacement and about inside the tank (1), a cellular structure is defined, while the beam elements (28A) oriented in one direction are superimposed on the beam elements (28B) oriented in the other direction, with the successive formation of horizontal layers from the lower wall (4) to the upper wall ( 3) of the tank (1), while the wall structure is fixed by the internal cellular structural system (5) under conditions of a self-balancing tension load, so that the pressure of the fluid on the wall (2) of the tank is transmitted to the internal cellular structural system (5). 18. The structural system (5) according to 17, in which the wall structure (2) of the tank is fixed by the structural system under direct self-balancing pressure of the fluid acting on the opposite walls (2) of the tank, and the tensile load is transferred to the structural system (5 ) through anchor or fastening means (40, 40 '). 19. The structural system (5) according to 17, in which the longitudinal axes of the beam elements (28A) in one layer are oriented essentially parallel, while in the plane of the beam elements forming the layer following the first layer, there are beam elements ( 28B), the longitudinal axes of which are oriented across the beams (28A) of the first layer, and the specified layer-by-layer overlay is repeated to form the walls (20) of the cells, the beam elements (28A) in the first layer form part of the first wall (20) of the cells, and the beam elements ( 28B) in the second layer form part of the second walls (20) of cells located transversely with respect to the first wall with which it is joined in the interface zone (21). 20. The structural system (5) according to any one of paragraphs.17-19, in which the beam elements (28A, 28B) have a T-shaped or I-shaped profile in cross section. 21. The structural system (5) according to claim 19, in which the beam elements (28A, 28B) are made with the possibility of direct or indirect connection with the outer sheet layer (8) of the tank (1) using anchor or fastening means in such a way that The process of using the tank ensures the transfer of loads between the outer sheet layer (8) of the tank (1) and the structural system (5).

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