Corner structure for stationary fixed diaphragm-type storage tank

Abstract

The present utility model relates to devices for storing low-temperature fluid media, and more particularly to corner structures for impermeable walls of hermetically sealed and thermally insulated diaphragm-type storage tanks for liquefied natural gas. A corner structure for a wall of a hermetically sealed storage tank comprises a first and a second panel (1), said panels containing thermally insulating layers arranged between plates (3, 4), wherein glued on top of one of the plates (4) of each panel (1) is a flexible sealing sheet (5). The first and second panels (1) are arranged edge-to-edge at an angle of 90 degrees and glued together, with the sealing sheets (5) on the inner side, forming a corner region. In the corner region, along the entire length of the panels (1), the sealing sheets (5) have a flexible impermeable sealing sheet (6) glued thereto which assumes a corner shape corresponding to the shape of the corner region. Glued to the join of the first and second panels (1), from on top of said sealing sheet (6), is a block (2) of thermally insulating material which is shorter in length than the first and second panels (1). The claimed corner structure is easier to manufacture and is more lightweight than existing prior art structures.

Description

[0001] CORNER DESIGN OF A STATIONARY MEMBRANE TYPE TANK

[0002] The field of technology to which the utility model belongs

[0003] This utility model relates to devices for storing low-temperature fluids. Specifically, the utility model relates to corner structures that can be used in the corners of stationary, sealed, membrane-type thermally insulated tanks installed on land or a floating platform.

[0004] State of the art

[0005] Sealed, insulated membrane-type tanks (also called membrane tanks) are used for low-temperature (cold) liquid media, in particular liquefied natural gas (LNG) - natural gas (primarily methane - CH4), artificially liquefied by cooling to a condensation temperature of -163°C for ease of storage or transportation.

[0006] The main advantage of LNG is that its volume is reduced by a factor of 600 during liquefaction. In practice, this means that the same volume of LNG contains three times more LNG than compressed natural gas at a pressure of 20 MPa. Liquefied natural gas is produced, stored, and transported using specialized cryogenic equipment. For commercial use, LNG is converted to a gaseous state at specialized regasification terminals.

[0007] Membrane tanks for cold liquid media, including LNG, contain insulating panels that are positioned next to each other to form thermal barriers.

[0008] Stationary tanks designed exclusively for storing low-temperature liquid fluids, i.e., without the possibility of transporting them, such as in tankers, do not experience dynamic loads, and therefore have less stringent requirements for the strength of their structural components. These tanks have a limited application: they are used only for storing low-temperature (cold) liquid fluids, particularly LNG. Tanks that do not experience dynamic loads can be installed either onshore or on a floating platform for the production, storage, and unloading of liquefied gas using a gravity-based structure (GBS).

[0009] From the publication US5501359 (A), 15.09.2000, prefabricated corner structures are known that provide liquid-impermeable and thermally insulated walls for a thermally insulated container, such as a tank for storing and / or transporting a liquid with a very low temperature. The insulation or heat-insulating system 4 of the structure 1 includes an internal insulation layer 42, to which a primary barrier is attached, as well as an external insulation layer 43, attached to an external supporting partition 3. In the corner parts of the structure 1, the insulation blocks 42 of the upper thermal insulation layer are joined via a connecting block 82, and the insulation blocks 43 of the lower thermal insulation layer have a joint 63 filled with a connector 80 made of a heat-insulating and liquid-impermeable material.All connectors 80 located in joints 63 are glued for hermetically sealed adhesion to the walls of the corresponding joint 63 in order to make the outer layer 43 continuous and impermeable to liquid over the entire surface defined by the design 1.

[0010] Disadvantages of this technical solution include the need for an additional manufacturing step to bevel the bottom layer 63 insulation blocks, requiring high precision to ensure proper joining of said blocks in the corner area. This also includes the use of connectors 80 located at the joints of the bottom layer 63 blocks, which complicates the manufacturing process for the corner structure and increases thermal insulation losses at the block joints. This, in turn, increases the manufacturing time for the corner structure. Furthermore, the interpanel space formed between the side faces of the bottom and top insulation layer panels consists of multiple spacers and inserts, further complicating the design.

[0011] Publication KR20220139785, dated October 17, 2022, describes a corner block consisting of lower blocks, upper blocks, and upper connecting blocks. The lower blocks are connected in the corner area by their respective beveled corners, while the upper blocks are joined using an additional connecting block. However, the design of the upper block connection is technically complex, which is a drawback of the known technical solution.

[0012] From the publication RU 2659691 C2, 03.07.2018, a corner block is known, which is installed in the corner of a tank and includes: a first lower panel 108, a second lower panel 108, a first auxiliary block 109 of insulating foam plastic, a second auxiliary block 109 of insulating foam plastic, a corresponding first sealing film 110, covering each of the auxiliary blocks 109 of insulating foam plastic, a second sealing film 111, glued to the first films 110 at the level of the connection between two blocks 109 of foam plastic, providing auxiliary tightness at the edge level and protruding on both sides of the edge, closing elements 233, 234, glued to the auxiliary sealing film 111, and reinforcing beads 235, 236, wherein the elements 233, 234 main thermal insulation layer are fastened with screws 114.

[0013] Publication RU2808190 C2, 24.11.2023 (prototype) discloses a method for manufacturing an angular structure (1) intended for manufacturing a sealed and thermally insulated tank. The angular structure consists of two layers: a primary layer and an auxiliary layer, wherein the primary layer is intended for contact with liquefied gas located inside the tank, and the auxiliary layer is the outer wall of the tank. The primary angular structure 19 of the tank includes a first block 20, a second block 21, a primary block of insulating foam 25 between the first block 20 and the second block 21, and a steel angle 22 located on the surface of the first 20 and second 21 blocks of the primary angular structure 19. The auxiliary angular structure is formed by a first panel 5, a second panel 6, and an insulating block 15. The primary angular structure 19 is fastened to the auxiliary angular structure.For this purpose, the first block 20 of the main corner structure 19 is fastened, for example, glued, to a part of the flexible sealed sheet 13 located on the outer surface 8 of the first panel 5. The second block 21 of the main corner structure 19 is fastened, for example, glued, to another part of the flexible sealed sheet 13 located on the outer surface 8 of the second panel 6. The disadvantage of the technical solution is the formation of an interpanel space between the blocks of the auxiliary corner structure, which is subsequently filled with an additional insulating block 15, while the thermal insulation losses that occur at the joints of the blocks increase, the method for producing the corner structure becomes more complicated, and the time for producing the corner structure increases due to the need for a technological operation to install an additional block.

[0014] Thus, to date, there is a need for technical solutions related to the angular structures of stationary membrane-type tanks, which, being simple design solutions, ensure high reliability of the tanks during operation.

[0015] Disclosure of a utility model

[0016] The technical objective of this utility model is to eliminate the deficiencies inherent in known technical solutions. This utility model simplifies the design of the corner element—the corner structure of a membrane-type tank—and its manufacturing method, thereby reducing production and assembly time.

[0017] The technical result of the utility model is achieved by the claimed corner structure for the wall of a sealed membrane-type tank for a low-temperature fluid medium, comprising first (1) and second (1) panels made from a layer of heat-insulating material with plywood plates (3,4) glued on both sides, in which a flexible impermeable sealing sheet (5) is glued on top of the plate (4) of each of the panels (1), wherein the first panel (1) is located end to end and glued to the second panel (1) on the side of the impermeable sealing sheet (5), forming a corner zone with an angle of 90°, wherein in the corner zone along the entire length of the panels (1) a flexible impermeable sealing sheet (6) is placed, glued to the sealing sheets (5) of the first (1) and second (1) panels and, thus, taking an angular shape corresponding to the shape of the said corner zone of the tank, and on top of the sealing sheet (6) a block (2) in the form of a rectangular parallelepiped is placed from thermal insulation material,the length of which is less than the length of the first (1) and second (1) panels, wherein two adjacent faces of the block (2) are glued to the sides of the flexible impermeable sealing sheet (6) of the said angular shape. The layer of thermal insulation material of the first (1) panel and the second (1) panel, as well as the block (2) of the angular structure can be made of a gas-filled polymer, in particular polyurethane foam or polyisocyanurate foam, having a density greater than or equal to 50 kg / m3.

[0018] The layer of thermal insulation material of the first (1) panel and the second (1) panel, as well as the block (2) can be made of fiber-reinforced gas-filled polymer, preferably fiberglass-reinforced or chopped carbon fiber-reinforced polyurethane foam.

[0019] The block (2) may have a chamfer along the entire length of the rib located between the faces of the block (2), which are glued to the sides of the sealing sheet (6) of an angular shape. The block (2) may be located at the same distance from the ends (7) of the first

[0020] (1) and the second (1) panels.

[0021] The first (1) panel and the second (1) panel at the corners, which are removed from their edge at a predetermined distance, contain mounting holes (8) for attaching the first and second panels (1) to the tank wall. The flexible impermeable sealing sheet (5,6) can be made of a composite material consisting of a layer of aluminum foil no less than 70 μm thick, reinforced on both sides with a layer of fiberglass.

[0022] Each side of the flexible impermeable sealing sheet (6) of angular shape may have a width equal to or greater than the width of the edge of the block (2) to which said sealing sheet (6) is glued.

[0023] The gluing of the first (1) and second (1) panels, block (2), plywood sheets (3,4), impermeable sealing sheets (5,6) can be carried out using polyurethane glue under the influence of force clamping loads. Brief description of the drawings

[0024] Fig. 1 shows a general view of the claimed angular design of a stationary tank.

[0025] Fig. 2 shows the component parts of the claimed angular structure “in flight”.

[0026] Fig. 3 shows a corner tank structure comprising a corner element and adjacent flat corner insulation panels. Fig. 4 shows the results of computer modeling of the claimed corner structure's displacement under load (temperature -163°C, pressure 0.17 MPa, displacement values ​​expressed in mm).

[0027] Implementation of the utility model Thermal insulation materials used in cryogenic engineering, in particular materials used for thermal insulation layers in insulation panels, are subject to a number of requirements, compliance with which ensures the possibility of their use in this field of technology. The main requirements for such materials are a low thermal conductivity coefficient, the absence of chemical interaction with the transported

[0028] LNG, with LNG tank construction materials, low hygroscopicity and density, ease of installation, operational reliability, compressive strength, etc.

[0029] Thermal insulation materials based on polyurethane foam and polyisocyanurate (PIR) foam are widely used in various engineering fields to create thermal insulation structural elements. Due to the rigidity of the foam, these elements can be formed into slabs or panels. Thermal insulation slabs and panels made from these materials possess the balance of physical and mechanical properties required for their intended application. Polyurethane foam, like polyisocyanurate, thanks to its rigid structure with gas-filled cells, is known for its excellent thermal insulation properties, combined with high fire resistance, high strength, and low thermal conductivity.

[0030] In addition to thermal insulation layers, the insulating panels also include other elements that ensure the characteristics required for their reliable operation, as well as the ability to attach these panels to other elements of the tank structure.

[0031] In accordance with the utility model, the claimed corner structure for the wall of a sealed membrane-type tank that is not subject to dynamic loads for a low-temperature fluid medium comprises first (1) and second (1) panels made of a layer of heat-insulating material with plywood plates (3, 4) glued on both sides, wherein the plywood plate (3) of each of the panels (1) forms the outer surface of the claimed corner structure, made with the possibility of being attached to the wall of the tank (Fig. 1 and Fig. 2). A flexible sealing sheet (5) impermeable to the low-temperature fluid medium is glued over the plate (4) of each of the panels (1), wherein in the claimed corner structure the sealing sheets (5) of each of the panels (1) face the inside of the tank and form the inner surface of the corner zone of the claimed structure. One side of the said inner surface is formed by the first (1) panel, and the other - by the second (1) panel.The first panel (1) is located end to end and glued to the second panel (1) on the side of the impermeable sealing sheet (5), forming a corner zone with the corner.

[0032] 90о. Thus, each of the panels (1) along its entire length has a free edge on one side, and on the opposite side - a joint / connection with another panel (1), wherein in the corner zone, on top of the sealing sheets (5) of the first (1) and second (1) panels, along their entire length, a flexible sealing sheet (6) impermeable to a low-temperature fluid medium is placed and glued. As a result of such placement and gluing, the flexible sealing sheet (6) takes an angular shape corresponding to the shape of the said corner zone, wherein the sides of the sealing sheet (6) of the angular shape are glued to the inner surface of the corner zone, i.e. to the sealing sheets (5) of the first (1) and second (1) panels.A block (2) in the form of a rectangular parallelepiped made of heat-insulating material, the length of which is shorter than the length of the first (1) and second (1) panels, is placed on top of the impermeable sealing sheet (6), and two adjacent faces of the block (2) are glued to the sides of the impermeable sealing sheet (6) of the said angular shape. Since several angular structures are located along one wall in the LNG storage tank, between the ends of which there is an interpanel space filled with a thermal insulation insert, the auxiliary sealing barrier formed by the impermeable sealing sheets (5,6) is interrupted. In order to ensure the continuity of the auxiliary sealing barrier at the joints of adjacent angular structures, the block (2) is made shorter than the panels (1).This design of the corner structure makes it possible to place and glue an additional auxiliary sealing membrane over the specified joints, ensuring continuous sealing of the auxiliary barrier.

[0033] According to the utility model, the first (1) and second (1) panels form the lower (located closer to the tank's supporting structure) thermal insulation barrier of the corner structure, have the same length, and are made in the form of blocks made of a layer of thermal insulation material, shaped like a rectangular parallelepiped, with plywood sheets (3, 4) placed on both sides (Fig. 1). It should be understood that the aforementioned rectangular shape of the parallelepiped of the first (1) and second (1) panels also includes a square shape.

[0034] For plywood sheets (3.4), it is preferable, but not mandatory, to use birch veneer with a thickness of 8-12 mm. This plywood has a flexural modulus of 9000-11000 MPa (at a temperature of +23°C). Plywood with such modulus values ​​possesses optimal properties for use in the claimed utility model.

[0035] The block (2) is intended to provide thermal insulation in the corner zone formed by the first and second panels (1) and is, in essence, the upper (main) thermal insulation barrier of the claimed corner structure.

[0036] According to the utility model, the thermal insulation layer (thermal insulation layer) for the first (1) and second (1) panels, as well as the block (2) in the claimed corner structure, are made of gas-filled polymers. Various gas-filled polymers, including reinforced ones, with low thermal conductivity and a sufficiently high degree of rigidity, can be used as materials for the thermal insulation layers. For example, foamed polyurethane (polyurethane foam) or polyisocyanurate (polyisocyanurate foam) can be used as a gas-filled polymer, preferably having a density of 50 kg / m3, in particular from 50 to 130 kg / m3, and a thermal conductivity of no more than 0.024 W / (m*K) (at a temperature of +10°C).

[0037] According to the utility model, the block (2) and the thermal insulation layer for the first (1) and second (1) panels are preferably made of fiber-reinforced gas-filled polymer, preferably fiberglass- or chopped carbon fiber-reinforced polyurethane foam. However, other gas-filled polymers suitable for this purpose may also be used.

[0038] As a reinforced thermal insulation material in the present utility model, it is possible to use, for example, a layer of polyurethane foam with chopped carbon fiber in the form of a plurality of discrete segments with a length of 500 μm to 15 mm and a diameter of 5 to 12 μm each, distributed and spatially oriented in the foam uniformly in all directions (RU228862, 12.09.2024).

[0039] Flexible impermeable sealing sheets (5, 6) are an auxiliary sealing membrane (auxiliary sealing barrier) in the tank, which provides vapor insulation and is resistant to hydrostatic pressure of liquid in the event of a breach of the tank's tightness due to damage to the primary membrane (corrugated membrane sheets of the impermeable wall of the tank), which is the main sealing barrier of the tank.

[0040] The impermeable sealing sheet (6) is designed to provide waterproofing properties to the corner structure at the junction of the first (1) and second (1) panels, i.e., in the corner zone of the claimed structure, in the event of a breach of the tank's primary sealing barrier. The corner-shaped sealing sheet (6) covers / encloses the inner surface of the corner zone of the claimed structure along the entire length of the first (1) panel and the second (1) panel.

[0041] There are no strict requirements for the width of the sides of the flexible sealing sheet (6), which takes on an angular shape as a result of its placement and gluing in the corner area. As a rule, to ensure reliable sealing of the auxiliary barrier at the junction of the first (1) and second (1) panels, the width of each side of the angular sealing sheet (6) is determined by the dimensions of the side faces of the block (2) and is equal to (i.e. not less than) the width of the side face with which the block (2) is glued to the sealing sheet (6), but may be greater than the width of the face of this block (2). The impermeable sheet (6) ensures the continuity of the auxiliary sealing barrier in the corner area, which directly affects the reliability of the tank as a whole: the continuity of the auxiliary sealing barrier ensures the tightness of the tank wall, and, consequently, the reliability of its insulating properties.

[0042] According to the utility model, the impermeable sealing sheets (5,6) are flexible because they are made of a composite material consisting of aluminum foil reinforced on both sides with layers of fiberglass, preferably bonded together with layers of polyurethane by thermocalendering or lamination. The aluminum foil is preferably at least 70 µm thick, providing the impermeable sealing sheets (5,6) with strength, vapor barrier properties, and resistance to hydrostatic pressure. Fiberglass imparts high tensile strength to the sheets (5,6), while polyurethane is a necessary auxiliary component for high-quality thermocalendering or lamination. These manufacturing technologies enable high interlayer adhesion of the fiberglass to the aluminum foil.

[0043] According to the utility model, the block (2) preferably has a chamfer (bevel) along the corner, with which the block (2) is glued to both sides of the impermeable sealing sheet (6) of an angular shape (Fig. 2). Since the sealing sheet (6) is flexible and is glued to the inner surface of the corner zone of the claimed structure, formed by the first (1) panel and the second (1) panel, an angular rounding of the sealing sheet (6) is formed at the junction of said panels (1). In order to prevent the occurrence of stress between the materials of the block (2) and the sealing sheet (6), a chamfer / bevel is made in the block (2) along the entire length of the rib located between the faces with which said block (2) is fastened to the sealing sheet (6).

[0044] According to the utility model, block (2) has a length shorter than the first (1) and second (1) panels. This embodiment of the corner structure allows for subsequent gluing of the auxiliary sealing barrier elements, which are positioned between two adjacent corner elements above the interpanel insert, overlapping to create continuity of the auxiliary sealing barrier. Block (2) is preferably located at an equal distance from the ends (7) of the first (1) and second (2) panels (Fig. 1).

[0045] The installation / adhesion of the corner structure to the tank wall is accomplished by applying beads of mastic to the outer surface of the corner, and then attaching the corner structure to the supporting wall of the tank using mechanical means, for example, by tightening nuts onto studs. To secure the claimed corner structure to the tank walls using the aforementioned mechanical means, mounting holes (8) (Fig. 1 and Fig. 3) may be made in the first (1) and second (1) panels, primarily in the corners that are spaced a predetermined distance from their edges. The number of mounting holes (8) and the distance from the edge of the first (1) and second (1) panels is determined individually in each case, depending on the location of the corner structure and its dimensions.In accordance with the utility model, in the claimed corner structure, gluing of the first (1) and second (1) panels, block (2), plywood plates (3,4), as well as flexible impermeable sealing sheets (5,6) can be carried out using polyurethane glue under the influence of force clamping loads.

[0046] The method for manufacturing the claimed corner structure is described below and includes the following stages:

[0047] 1. Rigid plywood sheets (3,4) are glued to the bottom and top sides of a block of thermal insulation material, such as polyurethane foam or polyisocyanate foam, using polyurethane glue, forming the first (1) panel and the second (1) panel.

[0048] 2. An impermeable sealing sheet (5) is glued to the plywood plate (4) of each of the panels (1) using polyurethane glue, which completely covers the plywood plate (4) of each of the panels (1).

[0049] 3. Prepare two panels (1), obtained in the previous stages, of the required shape and size, which can be done by cutting from large-sized panels.

[0050] 4. The first (1) panel and the second (1) panel are placed in a position in which the side edge of the first (1) panel is located end-to-end with the second (1) panel on the side of the impermeable sealing sheet (5) of the second (1) panel at an angle of 90° and the first (1) panel is glued to the second (1) panel using polyurethane glue. Thus, the impermeable sealing sheets (5) of the first (1) and second (1) panels form the inner surface of the corner zone obtained as a result of gluing the panels (1) of the claimed design, wherein the plywood plates (3) of the first (1) panel and the second (1) panel form the outer side of the said corner zone (Fig. 1 and Fig. 2).

[0051] 5. Glue a flexible impermeable sealing sheet (6) onto the inner surface of the resulting corner zone using polyurethane glue, i.e. on top of the flexible impermeable sealing sheets (5).

[0052] In this way, a lower (auxiliary, located closer to the supporting structure of the tank) insulating layer of the corner structure is formed, which includes the first (1) panel and the second (1) panel, containing a heat-insulating layer, plywood plates (3,4), which impart rigidity to the corner structure, and impermeable sealing sheets (5, 6), forming an auxiliary sealing barrier of the claimed corner structure.

[0053] 6. Prepare a block (2) in the form of a rectangular parallelepiped made of thermal insulation material, for example, fiberglass-reinforced or chopped carbon fiber-reinforced polyurethane foam, and preferably chamfer / bevel one corner along the entire length of the edge of the block (2).

[0054] 7. Glue two adjacent, i.e. located perpendicular to each other, side faces of the block (2) to the inner surface of the corner zone of the structure on top of the sealing sheet (6), for example, using polyurethane glue, while in the preferred case the block (2) is positioned with the chamfer towards the joint of the first (1) and second (1) panels.

[0055] 8. Make mounting holes (8) in the corners of the first (1) and second (1) panels, located at a predetermined distance from the edges of said panels (1) and from the block (2), since the length of the block (2) is always less than the length of the first (1) and second (1) panels (Fig. 1 and

[0056] Fig.3). The resulting angular structure is ready for installation in the tank.

[0057] Subsequently, two connecting thermal insulation panels (9) having a thickness equal to the size (thickness) of the side edge of the block (2) are glued to the two free, i.e. those that remain unglued, side faces of the block (2) of the corner structure in such a way that an internal angle of the tank wall is formed, which will be located under the main sealing membrane, forming a single plane with the adjacent flat insulation panels. Fig. 3 shows the corner structure according to the utility model assembled with connecting insulation panels (9), as well as with attached flat insulation panels (10) containing anchor plates (11), to which the main sealing barrier - the primary membrane (not shown) will subsequently be attached. Between the adjacent corner structures there is an interpanel space, which, after the installation of the said structures, is filled with interpanel inserts made of thermal insulation material.

[0058] The advantage of the proposed corner structure is that, unlike prior art solutions, it does not contain multiple components such as metal angles, plywood blocks, etc., making it lighter, easier to manufacture, and more convenient to install. Furthermore, unlike the prototype, the lower thermal insulation layer does not contain additional insulation blocks and, consequently, additional joints that could lead to thermal losses.

[0059] Figure 4 shows the results of computer simulation confirming that, when using the proposed corner element design—the corner structure—no large displacement values ​​(the "total deformation" on the Y-axis) are observed under static loads, such as cryogenic temperatures (approximately -163°C) and a pressure of 0.17 MPa generated inside the tank, under which it operates. This means that this corner structure is sufficiently robust and can be used in membrane-type tanks, which do not experience dynamic loads during operation.

Claims

Invention formula 1. A corner structure for the wall of a sealed membrane-type tank for a low-temperature fluid medium, comprising first (1) and second (1) panels made from a layer of heat-insulating material with plywood plates (3,4) glued on both sides, in which a flexible impermeable sealing sheet (5) is glued on top of the plate (4) of each of the panels (1), wherein the first panel (1) is located end-to-end and glued to the second panel (1) on the side of the impermeable sealing sheet (5), forming a corner zone with an angle of 90°, wherein in the corner zone along the entire length of the panels (1) a flexible impermeable sealing sheet (6) is placed, glued to the sealing sheets (5) of the first (1) and second (1) panels and, thus, taking an angular shape corresponding to the shape of the said corner zone of the tank, and on top of the sealing sheet (6) a block (2) in the form of a rectangular parallelepiped made of heat-insulating material is placed,the length of which is less than the length of the first (1) and second (1) panels, wherein two adjacent faces of the block (2) are glued to the sides of the flexible impermeable sealing sheet (6) of the said angular shape.

2. The corner structure according to item 1, in which the layer of thermal insulation material of the first (1) panel and the second (1) panel, as well as the top block (2) are made of a gas-filled polymer, in particular polyurethane foam or polyisocyanurate foam, having a density greater than or equal to 50 kg / m3.

3. The corner structure according to claim 1, in which the layer of thermal insulation material of the first (1) panel and the second (1) panel, as well as the block (2) are made of fiber-reinforced gas-filled polymer, preferably fiberglass-reinforced or chopped carbon fiber-reinforced polyurethane foam.

4. The corner structure according to claim 1, in which the block (2) has a chamfer along the entire length of the rib located between the faces of the block (2), which are glued to the sides of the sealing sheet (6) of the corner shape.

5. The corner structure according to claim 1, in which the block (2) is located at the same distance from the ends (7) of the first and second panels (1).

6. The corner structure according to claim 1, in which the first (1) panel and the second (1) panel in the corners, which are removed from their edge by a given distance, contain mounting holes (8) for attaching the first and second panels (1) to the wall of the tank.

7. The corner structure according to claim 1, in which the flexible impermeable sealing sheet (5,6) is made of a composite material consisting of a layer aluminum foil with a thickness of at least 70 microns, reinforced on both sides with a layer of fiberglass.

8. The corner structure according to claim 1, in which each side of the impermeable sealing sheet (6) of the corner shape has a width equal to or greater than the width of the edge of the block (2) to which said sealing sheet (6) is glued.

9. The corner structure according to item 1, in which the gluing of the first (1) and second (1) panels, block (2), plywood plates (3,4), impermeable sealing sheets (5,6) is carried out using polyurethane glue under the influence of force clamping loads.

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