Method for producing a sealed tank for containing a gas and / or fluid

Abstract

Relates to a method for producing a sealing wall of a sealed storage tank, comprising: assembling a mandrel; forming a sealing wall of the storage tank on the outer surface of the mandrel, and simultaneously forming an extraction hole for extracting the mandrel; removing the mandrel from the sealing wall via the extraction hole, the step of forming the sealing wall being performed by performing the following sub-steps: forming the enclosure by applying a knitwear covering the outer surface of the mandrel, the knitwear comprising a layer of knitting threads forming a plurality of loops, the knitting threads being made of a thermoplastic material that can be sealed by heating; winding a plurality of contiguous sections of a first strip comprising a thermoplastic material sealable by heating and reinforced by fibers around the enclosure such that the plurality of contiguous sections of the first strip overlap to form a first layer of the first strip and so as to form a superimposed layer of the first strip; the enclosure and the wound first strip are cooled so as to form the sealing wall in the form of a single material. The invention also relates to a method for producing a sealed tank for containing a gas or a liquid.

Description

Technical Field

[0001] The technical field of the present invention relates to a method for producing a sealed tank or a sealed container, in particular but not limited to a pressurized tank made of a composite material.

[0002] The invention relates to a method for producing a sealed tank using a thermoplastic material reinforced with fibers in a production process. Background Art

[0003] Recently, the storage conditions of gases or liquids have been improved with the advent of composite sealed storage tanks that contain fibrous materials (ie, materials reinforced by fibers) as wall structures or outer envelopes.

[0004] A "sealed tank" is a tank or container that is sealed against liquids and / or gases. More specifically, it is a tank that has a permeability to these liquids and / or these gases that is below the maximum limit specified by the application.

[0005] For example, a sealed storage tank designed for transporting hydrogen in compressed form at high pressure may be permeable to hydrogen when the hydrogen is compressed to a pressure in the range of 30 MPa to 70 MPa (ie, 300 bar to 700 bar).

[0006] In order to allow the storage of hydrogen under these pressure conditions, it is known to use sealed tank architectures known as type III or IV. Such architectures comprise, from the inside to the outside, a sealed cylinder (also known as a "liner" according to the terminology currently used) and an external reinforcement structure made by means of filament winding.

[0007] The purpose of the inner lining is primarily to ensure the gas-tight function (it must be as impermeable as possible to hydrogen). The purpose of the outer reinforcement structure is primarily to ensure the mechanical resistance to pressure.

[0008] In Type III tanks, the liner is made of metal. In Type IV tanks, the liner is made of polymer and is produced by, for example, rotational molding or extrusion blow molding.

[0009] A new type of tank is described in the document WO2011143723A2. There, the gas seal is not provided by means of a metal liner. Therefore, the liner is replaced by an internal sealing shell, which is formed by winding and heating a covering strip formed by a thermoplastic material, which can be sealed by heating around a template (or mandrel). This template is made of metal and can be disassembled into a plurality of rings, which are circumferentially fitted to each other, thus allowing it to be disassembled and reusable. The template also has a shape corresponding to the shape of the tank. Typically, the template has a cylindrical shape and has a rounded / circular front end face in the form of a cap on each axial side.

[0010] To ensure mechanical strength and consolidate the barrier to the gases, the sealed inner enclosure is protected by a second enclosure, called protective outer enclosure, also made by winding a strip containing a thermoplastic material sealable by heat and reinforced by preferably continuous fibers. This second enclosure constitutes the outer reinforcement structure of the sealed tank.

[0011] Similar to the inner shell, the outer shell is formed by winding a cover strip on the first shell (the first shell thus acts as a mandrel), wherein the material of the wound cover strip is a fiber-reinforced thermoplastic material. Thus, the final sealing wall of the sealed tank comprises two parts (i.e., the inner shell and the outer shell).

[0012] Since the inner sealing shell formed by the thermoplastic material wound strip is much lighter and less expensive than the liner (made of metal and polymer), the use of this inner sealing shell can significantly reduce the weight and cost of the tank.

[0013] However, this advantage is balanced by an increase in the production time of the sealed tank, since the winding of the cover strip during the production of the sealed inner shell requires a lot of time. In fact, since the cover strip is narrow and thin compared to the size of the template and the required thickness of the sealed inner shell, it must be wound around the template several times. In particular, the cover strip is wound to form a plurality of overlapping turns that overlap longitudinally and radially, thereby forming a plurality of layers around the template. In addition, the winding speed is limited by the pressure and tensile forces to be applied to the cover strip so that the first layer is well clamped on the template and the subsequent layers are clamped relative to each other. This makes it possible to avoid the generation of bubbles between each turn and layer during the heating step, which makes it possible to melt or soften the turns relative to each other in order to merge them.

[0014] For example, several hours are required to wind a strip with a thickness of 120 to 150 microns and a width of 25 to 80 millimeters around a cylindrical template with a diameter of 60 centimeters and a length of 3.50 meters to a thickness of 2 to 5 millimeters. This type of duration prevents the deployment of production methods on an industrial scale.

[0015] Therefore, it is necessary to speed up the production of sealed storage tanks, especially the production of sealed storage tanks without lining. Summary of the invention

[0016] The present invention provides a solution to the aforementioned problems by enabling a sealed wall to be obtained in a single step of winding the fiber-containing material.

[0017] A first aspect of the present invention relates to a method for producing a sealing wall of a sealed storage tank, the sealed storage tank being designed to contain gas and / or liquid, the production method comprising the following steps:

[0018] - Assembling a reusable and removable mandrel by assembling / disassembling a plurality of rings, the mandrel having an outer surface whose shape corresponds to the inner surface of the sealing wall of the tank;

[0019] - forming a sealing wall of the tank on the outer surface of the mandrel and forming an extraction hole for extracting the mandrel;

[0020] - Removing the mandrel from the sealing wall via the extraction hole.

[0021] The step of forming the sealing wall is performed by performing the following sub-steps:

[0022] - forming the capsule by applying at least one knitted fabric covering the outer surface of the mandrel, the knitted fabric comprising a layer constituted by a knitted thread forming a plurality of loops, the knitted thread being made of a thermoplastic material capable of being sealed by heating;

[0023] - winding around an enclosure formed by knitted fabric covering the outer surface of the mandrel successive sections of a first strip of thermoplastic material sealable by heating and reinforced with fibers, so that successive sections of the first wound strip overlap so as to form a first layer of the first strip, and so that successive sections of the first strip overlap so as to form a superimposed layer of the first strip, the winding being carried out in the following manner:

[0024] - applying a selected pressure so as to clamp each section of the first wound strip to the capsule so as to form a first layer of the first strip, and so as to clamp sections of the first strip covering the first layer of the first strip so as to form further superimposed layers of the first strip, and

[0025] - applying a temperature selected so as to melt the thermoplastic material of each section of the first layer of the first strip and the underlying threads of the capsule, and so as to melt sections of successive layers of the first strip;

[0026] - Cooling the capsule and the first wound strip so as to form the sealing wall in the form of a single material.

[0027] Thus, the preliminary use of a knitted fabric whose threads / coils are made of a thermoplastic material compatible with the thermoplastic material of the first strip (the two components melt together under the combined effect of the pressure and temperature applied during winding) advantageously makes it possible to dispense with the highly time-consuming step of winding the thermoplastic strip on a mandrel. Thus, the production process of the sealing wall of the sealed tank is carried out more quickly than according to the solutions proposed in the documents of the prior art.

[0028] In fact, a single knit (or a single layer of knit) provides sufficient thermoplastic material by melting with / with the first strip to produce a gas barrier effect with the same mechanical pressure resistance as the sealed internal enclosure of the tank according to the prior art. Since the knit is pre-produced, it does not need to be formed during the production process of the tank, contrary to the sealed internal enclosure of the tank according to the prior art. The knit can also be applied to the mandrel quickly and easily, since it can simply be slid onto the mandrel, for example manually.

[0029] Furthermore, thanks to the fact that the threads / loops of the knitted fabric are made of a thermoplastic material compatible with the thermoplastic material of the first strip, the sealing wall obtained is in the form of a single piece, i.e. formed from a single material. In other words, once the winding of the first strip has been completed, it is not possible to distinguish / separate the components / constituents used (knitted threads and thermoplastic material impregnated with reinforcing fibers). This uniformity of the present sealing wall makes it possible to improve the strength of the tank compared to a sealing wall composed of two enclosures, inner and outer, such as exists in solutions according to the prior art.

[0030] In particular, when a vacuum or reduced pressure is applied to the interior of a sealed tank, the single-piece sealed wall of the tank is more resistant than a double-layer wall. Since these pressure and temperature conditions are encountered during the drying and purification phase of the tank or during the emptying phase, the resulting sealed tank is more suitable for its use and has a longer service life.

[0031] In addition to the features just described in the preceding paragraphs, the method according to the first aspect of the invention may also have one or more complementary features selected from the following, considered individually or in all technically possible combinations:

[0032] - the thermoplastic material of the knitting thread is the same as the thermoplastic material of the first strip;

[0033] -The mass per unit surface area of ​​knitted fabric is 100g / cm 2 Up to 800g / cm 2 within the scope of

[0034] - the knitted article is in the form of one or more sleeves, each sleeve being slid onto / from one end of a mandrel;

[0035] - the sub-step of forming the enclosure also comprises applying a second knitted fabric to the first knitted fabric, wherein the thermoplastic material of the knitted threads of the second knitted fabric can be sealed by heating under the same temperature and pressure conditions as the thermoplastic material of the knitted threads of the underlying first knitted fabric;

[0036] The sub-step of winding around the capsule comprises winding at least one other additional strip formed from the material of the first strip, wherein said additional strip is wound simultaneously with said first strip.

[0037] A second aspect of the present invention relates to a method for producing a reinforced sealing wall of a storage tank, the method comprising the steps of the sealing wall method described above with or without different embodiments, the method comprising the following sub-steps:

[0038] - winding around the sealing wall successive sections of a second strip comprising a thermoplastic material sealable by heat and reinforced with fibers, so that successive sections of the second wound strip overlap in order to form a first layer of the second strip, and so that successive sections of the second wound strip overlap in order to form a superimposed layer of the second strip, the winding being carried out in the following manner:

[0039] - applying a selected pressure so as to clamp each section of the second wound strip against the sealing wall so as to form a first layer of the second strip, and so as to clamp sections of the second strip overlapping the first layer of the second strip so as to form further superimposed layers of said second strip; and

[0040] - applying a temperature selected so as to melt the thermoplastic material of each section of the first layer of the second strip and the underlying region of the sealing wall, and so as to melt sections of successive layers of the second strip;

[0041] - Cooling the sealing wall and the second strip so as to form a reinforced sealing wall made of a single material.

[0042] Therefore, the sealing wall of the tank is reinforced with fibers and thermoplastic materials. This makes it possible to increase the sealing and the mechanical resistance to the tank pressure.

[0043] Advantageously, the thermoplastic material of the knitting threads of the knitted fabric is the same as the thermoplastic material of the first strip.

[0044] Thus, the capsule and the second winding strip are joined together in as perfect a manner as possible.

[0045] A third aspect of the present invention relates to a method for producing a sealed storage tank for containing gas or liquid, the method comprising the following steps:

[0046] - producing a sealing wall of a tank by carrying out the steps of the production method according to the first aspect of the invention as described above with or without different embodiments;

[0047] - closing the sealing wall by applying a bottom against / against the sealing wall;

[0048] - reinforcing the sealing wall in order to obtain a reinforced sealing wall of the tank,

[0049] The step of reinforcing the sealing wall is performed by performing the following sub-steps:

[0050] - winding around the sealing wall successive sections of a second strip comprising a thermoplastic material sealable by heating and reinforced with fibers, so that successive sections of the second wound strip overlap in order to form a first layer of the second strip, and so that successive sections of the second wound strip overlap in order to form a superimposed layer of the second strip, the winding being carried out in the following manner:

[0051] - applying a selected pressure so as to clamp each section of the second wound strip against the sealing wall so as to form a first layer of the second strip, and so as to clamp sections of the second strip overlapping the first layer of the second strip so as to form further superimposed layers of said second strip; and

[0052] - applying a temperature selected so as to melt the thermoplastic material of each section of the first layer of the second strip and the underlying region of the sealing wall, and so as to melt sections of successive layers of the second strip;

[0053] - Cooling the sealing wall and the second strip so as to form a reinforced sealing wall made of a single material.

[0054] The thermoplastic material of the second strip is therefore chemically compatible with the underlying region of the sealing wall so as to melt / fuse together.

[0055] According to one embodiment, the thermoplastic material of the first strip and the thermoplastic material of the second strip are the same.

[0056] According to one embodiment, the outer peripheral surface / peripheral surface of the bottom is covered with a thermoplastic material, which can be sealed by heating and is compatible with the thermoplastic material of the sealing wall. According to one example, the outer peripheral surface of the bottom is heated before the closing step so as to melt / fuse together with the inner and outer peripheral surfaces of the sealing wall defining the extraction hole during the step of closing the sealing wall.

[0057] According to one embodiment, during the step of reinforcing the sealing wall, the outer surface of the bottom is covered by a second strip.

[0058] The invention and its various applications may be better understood by reading the following description and examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The drawings are provided for illustration purposes and do not limit the invention in any way.

[0060] Figure 1 The main steps of the method for producing a sealed storage tank according to one aspect of the present invention are shown in the form of a logic diagram;

[0061] Figure 2 is based on Figure 1 A schematic cross-sectional view of a sealed storage tank obtained by the production method shown;

[0062] Figure 3 The main steps of the method for producing a sealing wall are shown in the form of a logic diagram, namely Figure 1 The first step of the production method shown;

[0063] Figure 4 The schematic diagram shows the Figure 3 Examples of mandrels used in the production method shown;

[0064] Figure 5 The logic diagram shows Figure 3 The second step of the production method shown;

[0065] Figure 6 The schematic diagram shows the Figure 5 Examples of knitwear used in the steps shown;

[0066] Figure 7 The schematic diagram shows the Figure 5 The semi-finished sealing wall produced in the first sub-step of the step shown;

[0067] Figure 8 The schematic diagram shows Figure 5 The second sub-step of the step shown;

[0068] Fig. 9The schematic diagram shows the Figure 5 In a third sub-step of the step shown, an assembly is formed into a sealing wall around the mandrel;

[0069] Fig.10 The schematic diagram shows the Figure 3 The sealing wall obtained after the third step of the production method shown;

[0070] Fig.11 The schematic diagram shows the Figure 1 A semi-finished tank in the second step of the production method shown;

[0071] Fig.12 The logic diagram shows Figure 1 A sub-step of the third step of the production method shown;

[0072] Fig.13 Shown in schematic form Fig.11 The first sub-step of the step shown;

[0073] Fig.14 A sub-step is shown schematically, which is Fig.13 An alternative to the first sub-step shown in;

[0074] Fig.15 The schematic diagram shows the Fig.12 The tank obtained after the second sub-step of the steps shown. DETAILED DESCRIPTION

[0075] Unless specified otherwise, identical elements appearing in different figures have the same unique reference numerals.

[0076] The present invention belongs to the category of sealed storage tanks and methods for their production. More particularly, the object of the present invention is to produce more quickly sealed storage tanks having a pressure resistance greater than 0.2 MPa and gas barrier properties (permeability / impermeability to gases and / or liquids contained in the sealed storage tank) similar to or better than prior art solutions.

[0077] Figure 1 An embodiment of a method 200 for producing a sealed storage tank according to the present invention is shown in the form of a logic diagram.

[0078] The method 200 for producing a sealed storage tank is preferably used to produce a sealed storage tank 1 (hereinafter also referred to as "storage tank 1"), an enlarged cross-sectional view of which is shown in FIG. Figure 2 shown.

[0079] In particular, the storage tank 1 is a composite material storage tank, which is designed for the field of transportation and delivery of high-pressure hydrogen.

[0080] A "composite tank" refers to a tank in which a gas sealing function is provided by a thermosetting material and a mechanical pressure resistance function is provided by a fiber-reinforced material. Therefore, the tank 1 is designed to contain hydrogen maintained at a high pressure of 700 MPa or higher. In this case, the tank is also designed to contain liquids such as water. It should be understood that in other examples, the tank 1 may be designed to contain other gases and / or other liquids under atmospheric storage conditions or at a pressure of less than 700 MPa.

[0081] like Figure 2 As shown, in this case, the sealed storage tank 1 has a cylindrical inner shape and an outer shape, which in this example extend along a single longitudinal axis XX'. The outer shape and the inner shape may have axes that deviate from each other, for example axes that are parallel to each other. The storage tank 1 includes a side surface on each axial side 1a, 1b, which is rounded and has the shape of a dome or a cap. In a number of other examples, the shape of the storage tank 1 may be different, for example, it may be spherical, ellipsoidal or other shapes.

[0082] In the following description, the terms "inside", "outside", "inner" and "exterior" are used to indicate the position of a component or a surface relative to the longitudinal axis XX' of the tank 1, wherein the interior or inner surface (for example) is closer to the longitudinal axis than the exterior or outer surface. The term "axial" refers to "in the direction along the longitudinal axis", and the terms "radial" and "transverse" refer to "in the direction perpendicular to the longitudinal axis". The term "lateral" means "on both sides of the radially extending portion". The terms "thickness" and "diameter" refer to dimensions measured radially. The term "length" refers to dimensions measured axially.

[0083] More specifically, again referring to Figure 2 , the tank 1 comprises a wall 11 and an inner volume 13. In this example, the tank 1 comprises a connection 12.

[0084] In this example, the diameter d of the inner volume 13 of the tank 1 is 13 is 60 cm, length l 13 3.50 meters.

[0085] The connection piece 12 of the storage tank 1 is a valve 12 which enables the passage of gas or liquid into and out of the storage tank 1 to be alternately closed / opened.

[0086] The wall 11 of the tank 1 has a sealing wall 111 and, in this example, a bottom 112 on one axial side 1 b of the tank 1 .

[0087] The sealing wall 111 of the wall 11 of the tank 1 has an inner surface 111 c having the shape of the inner volume 13 of the tank 1 .

[0088] The sealing wall 111 is made of a composite material, i.e. it contains a mixture of at least one thermoplastic material and at least one fiber material. The sealing wall 111 provides both an internal barrier effect (impermeability) to the gas or liquid contained in the internal volume 13 of the storage tank 1 and an effect of mechanical resistance to pressure. The thermoplastic material and fiber type of the sealing wall 111 will be described below in conjunction with the method 100 for producing the storage tank 1.

[0089] The bottom 112 of the wall 11 of the tank 1 is preferably annular, ie has an internal passage designed to accommodate the connection (valve) 12 .

[0090] exist Figure 2 In the example of the tank 1 shown, the bottom 112 advantageously has a curved outer surface 112a, at least the periphery of which is located in the thickness of the sealing wall 111 ( Figure 2 Thus, the sealing wall 111 and the bottom 112 forming the tank 1 are formed as a single rigid structure that can withstand the pressure required for the application.

[0091] Combined with the following Figures 1 to 15 A method 200 for producing a storage tank 1 is described.

[0092] like Figure 1 As shown, the method 200 for producing the storage tank 1 comprises the following consecutive steps:

[0093] - according to another aspect of the invention, the sealing wall 111 of the wall 11 of the tank 1 is produced according to the known production method 100;

[0094] - Closing E4 the sealing wall 111 by applying a seat against / against the sealing wall.

[0095] In addition, optionally, the method 200 further includes the following steps:

[0096] - Reinforcement E5 of the sealing wall 111 to obtain a reinforced sealing wall.

[0097] Combined with the following Figures 3 to 10 A method 100 for producing a sealing wall 111 is described.

[0098] refer to Figure 3 The method 100 for producing the sealing wall 111 comprises the following steps:

[0099] - Assembling E1 a reusable and removable mandrel 2 , the shape of the outer surface of which corresponds to the inner surface 111 c of the sealing wall 111 of the wall 11 of the tank 1 , by assembling / disassembling a plurality of rings 24 ;

[0100] - forming a sealing wall 111 of the wall 11 of the E2 tank 1 on the outer surface of the mandrel 2, and forming an extraction hole 111d for extracting the mandrel 2;

[0101] - Removal E3 of the mandrel 2 from the sealing wall 111 via the extraction hole 111d.

[0102] Figure 4 An example of an assembled mandrel 2 for use in the method 100 is schematically illustrated. This mandrel 2 is inspired by document WO2011143723A2.

[0103] The mandrel 2 acts as an inner mold / inner mould for the sealing wall 111 .

[0104] The mandrel 2 is suitable for fiber winding. In fact, as will be described below, step E3 of the method 100 uses such a method to wind the filaments around the mandrel 2.

[0105] like Figure 4 As shown, in this case the spindle 2 is a hollow rotating part having an axis of rotation 23 .

[0106] In this example, the spindle 2 comprises at one end a removable main shaft (or connection) at the axial end of the spindle 2. In this example, this main shaft 22 of the spindle 2 is designed to be coupled to a rotary motor so that the spindle 2 can rotate around its axis of rotation 23.

[0107] The spindle 2 also comprises a removable outer surface 21 which is integral with the main shaft 22 (once the assembly of the spindle 2 has been completed).

[0108] The outer surface 21 of the mandrel 2 has a rounded shape that matches the shape (and size) of the inner surface 111c of the sealing wall 111 of the wall 11 of the tank 1 (see Figure 2 Thus, according to the example of the tank 1 previously described, in this case the mandrel 2 has an outer surface 21 with a maximum diameter of 60 cm and a length of 3.50 m.

[0109] The spindle 2 includes a plurality of rings 24 and also includes a base 25 in this example. In this case, the base 25 includes a bottom 251 and a stopper 252 located in the bottom 251, but the base may be formed as a single piece. The outer surface of the spindle 21 includes each outer surface 214 extending axially from each ring 24, and an outer surface 215 of the base 25 positioned opposite to the main shaft 22 of the spindle 2. In this example, the outer surface 215 of the base 25 includes a bottom outer surface 2151 and a stopper outer surface 2152. Each ring 24 is held in place by its opposite ends, one end being fixed on the circumference 22a of the main shaft 22, and the other end being engaged in the bottom 251 of the base 25. According to another example, the rings 24 may also be fitted into each other.

[0110] The E1 spindle 2 is assembled by, for example, first coupling the main shaft 22 to a rotating tool, then engaging one end of each ring 24 in the main shaft 22 , and finally fixing the opposite end of the ring 24 with the base 25 of the spindle 2 .

[0111] It will be appreciated that other configurations of the spindle 2 are possible (not shown).

[0112] Figure 5 Step E2 of the method 100 is shown in the form of a logic diagram. As previously mentioned, this step E2 aims at forming the sealing wall 111 of the wall 11 of the tank 1 .

[0113] like Figure 5 As shown, step E2 begins with a sub-step E21 . During this sub-step E21 , knitwear 3 is applied on mandrel 2 , covering the outer surface 21 of mandrel 2 .

[0114] Figure 6 A partial view of an example of a knitted fabric 3 is schematically shown.

[0115] like Figure 6 As shown, the knitted fabric 3 comprises a layer 31 consisting of knitted threads 311, 312 forming the loops. Therefore, the knitted fabric 3 is a structure that can be formed by interpenetrating loops or meshes. For example, the loops or meshes are formed by "head and foot interlacing". Therefore, the knitted fabric 3 forms a material whose mesh can be stretched in different directions and has greater elasticity than a woven fabric.

[0116] The knitted threads 311 , 312 are formed of a heat-sealable thermoplastic material or one of the heat-sealable thermoplastic materials of the sealing wall 111 (it should be noted that no sealing is performed in sub-step E21 ).

[0117] The thermoplastic material of the knitted fabric 3 is, for example, selected from (but not limited to) thermoplastic materials of the polyolefin family or the polyamide family.

[0118] Therefore, the knitted threads 311, 312 may be made of nylon. In this case, in particular, the diameter of the knitted threads 311, 312 may be in the range of 0.5 mm to 1 mm.

[0119] The knitting threads 311, 312 preferably form loops oriented in a first direction D1 and a second direction D2 perpendicular to the first direction D1. The thickness of the knitting threads 311, 312 and / or the geometry of the knitted fabric are determined so that after the knitted fabric 3 is applied to the outer surface 21 of the mandrel 2, the mass per unit surface area of ​​the knitted fabric 3 is within 100 g / m 2 Up to 800g / m 2 within the range.

[0120] Thus, after completing sub-step E21, the knitted threads 311, 312 of the knitted fabric 3 form a capsule 30 of knitted threads formed according to the periphery of the outer surface 21 of the mandrel 2. In other words, the capsule 30 of knitted threads has the shape of the circumference (outer limit) of the outer surface 21 of the mandrel 2 and is positioned in contact with this outer surface 21. In other words, the capsule 30 forms a net that is positioned flat / flat or covers / drapes the outer surface 21 of the mandrel 2.

[0121] This capsule 30 constituted by knitted threads provides the first part constituted by thermoplastic material of the sealing wall 111. As mentioned before, this or these thermoplastic materials are necessary to provide a barrier effect (impermeability) for the gas or liquid to be contained in the internal volume 13 of the tank 1.

[0122] Figure 7 The mandrel 2 obtained after completion of step E21 is shown, in this case covered by a capsule 30 consisting of knitted threads.

[0123] like Figure 7 As shown, the capsule 30 does not cover the main shaft 22 of the mandrel 2. Therefore, when the main shaft 22 is removed during step E3 of the method 100, a hole will remain (corresponding to the cross section of the main shaft 22), which hole will be referred to as "extraction hole 111d for extracting the mandrel 2" (see Fig.10 ), the ring 24 and the base 25 of the spindle 2 can be extracted from the inside of the sealing wall 111 through the hole. For this purpose, the spindle 22 (and therefore the extraction hole 111d) has a size depending on the ring 24, the bottom 25 and the stopper 26 so that they can be extracted.

[0124] In any case, a portion of the mandrel 2 is not covered by the capsule 30 to form the extraction hole 111d. According to another example not shown, the capsule 30 does not cover the outer surface 2152 of the stopper 252, so that the stopper can be removed and the extraction hole 111d or the second extraction hole is formed. In this example, the main shaft 22 can be only an internal shaft and can be covered by the capsule 30 and can be removed through the extraction hole 111d when the stopper is removed. In this case, during the manufacture of the sealing wall, the stopper 252 can act as a support and retainer for the mandrel 2, for example by making the axis 23 vertical.

[0125] In practice, the knitted fabric 3 is produced before the method 100 for producing the sealed tank 1 is carried out.

[0126] Advantageously, the knitted fabric is in the form of one or more sleeves (or socks) (not shown in the figures). These sleeves are stretchable and retractable because they are made of knitted threads 311, 312 only.

[0127] Thus, the sleeve is applied to the mandrel 2, for example by an operator, in the following manner: the sleeve is slid onto the mandrel 2 via one of its ends, in this case via the main axis 22 of the mandrel 2 or via the base 215 of the outer surface 21 of the mandrel 2. The sleeve stretches as it slides on, and then, once the sleeve is stretched and released, it retracts back onto the outer surface of the mandrel. Thus, the knitwear 3 is positioned spread / less stretched / flat on the outer surface 21 of the mandrel.

[0128] Advantageously, when the mandrel is of larger dimensions (for example when its length is greater than 1 meter), a plurality of sleeves are used.

[0129] In various other cases, multiple specially designed mandrels are used to conform to the different shapes (diameters) of the outer surface 21 of the mandrel 2. Thus, one sleeve may be used to cover the outer surface 214 of the ring 24 or a portion of the outer surface 214, and another sleeve may be used to cover the outer surface 215 of the base and optionally a portion or another portion of the outer surface 214 of the ring 24. The sleeves may be applied side by side, or they may overlap each other in the axial direction.

[0130] In any case, whatever the number of sleeves or the size of the mandrel (especially its length), the step E21 of applying the knitwear 3 is particularly fast and easy to perform. For example, a well-trained operator requires 10 minutes to form the capsule 30 around the mandrel 2. In other words, the portion of the thermoplastic material of the sealing wall 111 is simply and quickly added to the mandrel.

[0131] As a variant, another knitted fabric (not shown in the figure) can be applied to the aforementioned knitted fabric 3. This other knitted fabric is hereinafter referred to as the "second knitted fabric", and the previously provided knitted fabric is referred to as the "first knitted fabric". Therefore, the shell 30 is composed of two (i.e., the first and second) knitted fabrics stacked one above the other. This makes it possible to increase the amount of thermoplastic material of the shell 30 composed of knitted yarn. This variant is particularly suitable for increasing the permeability / impermeability of the sealing wall 111 (gas blocking effect).

[0132] When part of the thermoplastic material has been added (via the capsule 30) to the outer surface 21 of the mandrel 2, the purpose is to add another part of the thermoplastic material, as well as the fibers required to produce the gas barrier effect. This addition is described below in conjunction with Figure 8 is performed during the sub-step E22 described.

[0133] In this sub-step E22, if Figure 8 As shown, especially in Figure 8 As shown in the illustrated illustration, successive / continuous segments 41 of a first strip 4 of thermoplastic material which can be sealed by heating and which can be reinforced with fibers can be wound around an enclosure 30 of knitted thread.

[0134] In other words, in this sub-step E22 , a process of fiber-winding the first strip 4 onto the capsule 30 is carried out so as to cover the capsule 30 with fibers and thermoplastic material.

[0135] The fibers of the first strip 4 are preferably continuous fibers. This makes it possible to obtain a reinforcement structure with better performance and thus increases the mechanical resistance of the resulting sealing wall 111.

[0136] The fibers of the first strip 4 are made of a material selected from (but not limited to) the following materials: glass, carbon, metal, mineral, wool, cotton, linen, polyester, polypropylene, polyamide, basalt, Stretching thermoplastics, or mixtures of two or more of these materials.

[0137] The thermoplastic material of the first strip 4 is chemically compatible with the thermoplastic material of the knitted threads 311, 312. The expression "chemically compatible" means that the thermoplastic material of the knitted fabric 3 and the thermoplastic material of the first strip 4 have melting points and / or softening points falling within the same or similar temperature range.

[0138] The heat-sealable thermoplastic material of the first strip 4 may be the same as the thermoplastic material of the knitting threads 311, 312. For example, the thermoplastic material of the first strip and the thermoplastic material of the knitting threads may both be of the polyolefin family, or may also both be of the polyamide family.

[0139] The effects of this compatibility of the thermoplastic material of the first strip 4 and of the knitted thread 3 will be described later in connection with sub-step E23 .

[0140] The width of the first strip 4 is preferably 20 cm or more, for example equal to 20 cm, 50 cm or more. This makes it possible to perform sub-step E22 more quickly than if the first strip had a smaller width.

[0141] It should be understood that a first strip 4 having a width less than 20 cm is suitable for the method 100 , for example a first strip 4 having a width equal to 2 cm, 4 cm or 14 cm is also suitable.

[0142] In fact, in this example, during the execution of sub-step E22, the mandrel 2 is rotated by the main shaft 22. According to another example, the mandrel 2 and the capsule 30 are fixed, and the winder rotates around the mandrel 2 for fiber winding the first strip 4 on the capsule 30 so as to cover the capsule 30 with fibers and thermoplastic material. As described below, the strip is wound while being clamped on the capsule 30, so that during the fiber winding, pressure is applied between the strip 4 and the capsule 30 at a temperature within a predetermined temperature range so that the strip 4 melts or is bonded to the capsule 30.

[0143] like Figure 8 As shown in the inset of FIG. 1 , the plurality of segments 41 of the first strip 4 that are successively wound overlap to form a first layer 4101 of the first strip 4, and overlap to form a superimposed layer 40 of the first strip 4 (in Figure 8 The insert will be formed on the first layer 410 i , the second layer on i=1, in the axial direction of the arrow). The number n1 of superimposed layers of the first strip 4 depends on the diameter and geometry of the mandrel 2 (and therefore on the diameter and shape of the required internal volume 13 of the tank 1), as well as the required bursting pressure (i.e., above which the tank 1 can no longer resist the pressure and will deform). The number n1 of layers can range from n1=2 to several hundred, for example n1=200. Multilayer winding makes it possible to reduce permeability and increase the mechanical resistance to pressure of the resulting sealing wall 111.

[0144] Each layer 410 i The thickness of (i=1 to n) may be, for example, in the range of 50 μm to 300 μm. i Within (i=1 to n), the distance of overlap of the consecutive sections 41 of the first strip is in the range of 0 (corresponding to no overlap) to half the width of the first strip 4, and the overlap is according to a variable overlap angle.

[0145] During the winding of the first strip 4 , pressure and heat are applied to each successive winding section 41 of the first strip 4 .

[0146] The pressure applied to each section 41 of the first winding strip is determined in the following order: 1) in the first layer 410 i , i=1 during the formation to apply pressure to clamp the segment 41 to the capsule 30 consisting of the knitted thread, and 2) in the superposition layer 410 i , i=2 to n1 during the formation, pressure is applied to clamp the segment 41 to the lower layer 410 of the first strip 4 i-1 superior.

[0147] The heating temperature applied to each section 41 of the wound first strip is determined according to the properties of the thermoplastic materials used (in the first strip 4, in the capsule 30 constituted by the knitted threads). More specifically, the temperature falls within the melting range of these thermoplastic materials used (this melting range is common since these thermoplastic materials are compatible).

[0148] Therefore, in the first layer 410 of the first strip 4 i , i=1, the thermoplastic material of each winding section 41 melts or bonds with the threads of the capsule 30 consisting of knitted threads beneath it. In addition, during the formation of the superimposed layer of the first strip 4, the thermoplastic material of each winding section 41 melts or bonds with the underlying layer 410 of the first strip 4. i-1 link.

[0149] In other words, the temperature is chosen to melt the thermoplastic material of each section of the first layer of the first tape and the underlying threads of the capsule consisting of knitted threads, as well as to melt sections of successive layers of the first tape.

[0150] For example, when the thermoplastic material in question belongs to the polyolefin family or the polyamide family, the temperature is in the range of 160°C to 340°C.

[0151] Under the action of heat and clamping, the layer 410 of the first strip 4 i , the fibers i=1 to n1 are also connected to the thermoplastic material (thermoplastic material of the first strip 4, thermoplastic material of the capsule 30 consisting of the knitting thread).

[0152] Thus, after completion of sub-step E22 , the assembly of superimposed layers 40 of the first strip and the capsule 30 are joined or consolidated into a single material.

[0153] In this context, the expression "single material" is understood to be homogeneous / uniform, such that it is not possible to distinguish by the naked eye the materials used to produce it. Thus, the expression "made / formed from a single material" refers to a monolithic / integral structure rather than a sealed wall consisting of two concentric enclosures.

[0154] As a variant, sub-step E22 is not carried out using a single first strip 4, but rather using at least one other additional strip formed from the material of the first strip, which additional strip is wound simultaneously with the first strip 4. This makes it possible to accelerate the execution of this sub-step E22 and therefore to make the process / method 100 for producing a sealing wall 111 proceed more quickly.

[0155] The method 100 for producing the sealing wall 111 also comprises, during step E2, a sub-step E23. During this sub-step E23, the assembly of the superposition 40 of the first strip and the capsule 30 are cooled in order to harden them. This thus provides a sealing assembly 130 which is the sealing wall 111 of the tank 1. This assembly 130 can be separated from the mandrel 2.

[0156] Fig. 9 The assembly 130 obtained after completion of sub-step E23 and thus of sealing wall 111 is shown. It should be noted that this assembly 130 (like capsule 30 constituted by knitted thread) has an extraction orifice 111d situated at the level of main axis 22 of mandrel 2.

[0157] refer to Figure 3 Step E3 of the method 100 for producing the sealing wall 111 is implemented after step E2. Fig.10 It is shown in the form of a schematic diagram.

[0158] like Fig.10 As shown, step E3 consists in disassembling the mandrel 2 and extracting it from the interior of the assembly 130 via the extraction orifice 111d.

[0159] In practice, in step E3 , first the main shaft 22 of the spindle 2 is disassembled, then the rings 24 are disassembled and removed via the extraction orifice 111 d of the assembly 130 , and finally the seat 25 is disassembled and removed via the extraction orifice 111 d .

[0160] After step E3 is completed, the assembly 130 from which the mandrel 2 has been removed is formed into a sealing wall 130, 111 of the tank 1. This sealing wall 130, 111 is thus made of a single material (see Fig.10 ).

[0161] Thanks to the consolidation of the capsule 30 constituted by the knitted thread and the layer 40 of the wound first strip 4, the sealing wall 130, 111 has similar impermeability and mechanical resistance to pressure as the tank described in document WO2011143723A2, while being faster to produce.

[0162] In fact, to form the gas barrier layer, it is no longer necessary to produce a first filament winding structure in thermoplastic material. This lengthy step (in the example of tank 1, it requires more than three hours) is no longer necessary because it is replaced by sub-step E21 of method 100, which consists in forming capsule 30 consisting of knitted threads.

[0163] As mentioned previously, this sub-step E21 is very fast (in the example of tank 1, 10 minutes are sufficient) for the following reasons: because the knitted fabric 3 is pre-produced, because it can be applied very quickly and easily to the mandrel 2, and finally because a single layer 31 of knitted yarn is sufficient to provide a sufficient amount of thermoplastic material. In fact, the adjustment of the knitting parameters provides a knitted fabric of sufficient grammage to make it possible to use a single layer of knitted yarn.

[0164] In addition to its execution speed, the joining of the capsule 30 constituted by the knitted thread and the superimposed layer 40 of the first strip makes it possible to produce the sealing wall 130 in the form of a single material. This homogeneous material has several advantages: 1) it increases the resistance to the internal pressure of the sealing wall 130; and 2) it increases the impermeability with respect to liquids. This therefore makes it possible to obtain a sealing wall 130 that is better manufactured and more durable (or in other words, has a longer service life).

[0165] Finally, it should be noted that the thickness of this knitwear 3 is less than that of a conventional lining.

[0166] After the sealing wall 130 is produced, the method 200 for producing the storage tank 1 continues with step E4 and step E5 (see Figure 1 ).

[0167] Fig.11 Step E4 (the second step of the production method 200 ) is schematically illustrated.

[0168] like Fig.11 As shown, during step E4, the bottom 112 of the wall 11 of the tank 1 (see Figure 2 ) is applied against / against the sealing wall 130, for example in order to close the extraction hole 111d.

[0169] For example, the bottom portion 112 may be welded against the sealing wall 130 on the periphery of the extraction hole 111d. In another example, the bottom portion 112 may be fitted into the extraction hole 112.

[0170] The diameter of the inner passage of the bottom 112 is smaller than the diameter of the main shaft 22. In this example, the inner passage is advantageously designed to receive the second main shaft 6 (see Fig.11 ) so as to allow the sealing wall 130 to rotate around its axis XX'.

[0171] The outer periphery 112a of the bottom 112 may advantageously be made of a thermoplastic material which is sealable by heating and which is compatible with the material of the sealing wall 130 (ie with the thermoplastic material of the knitted threads and therefore with the thermoplastic material of the first strip 4).

[0172] For example, the bottom 112 may be entirely formed of such a thermoplastic material, or may have an overmolded structure consisting of such a material only on its outer periphery 112a (in which case the remainder of the bottom may be made of metal). The overmolded bottom may be easily welded to the sealing wall 130 .

[0173] Fig.12 Step E5 of the method 200 for producing a sealed storage tank 1 is shown in the form of a logic diagram. This step E5 aims to strengthen / reinforce or reinforce the sealing wall 130 with a fiber material in order to obtain a reinforced / reinforced sealing wall 150, which can therefore mechanically withstand pressures greater than 2 MPa, for example. Therefore, the sealing wall 111 of the storage tank 1 is a reinforced sealing wall 150.

[0174] like Fig.12 As shown, for this purpose, step E5 includes a sub-step E51 of fiber winding and a sub-step E52 of cooling the wound structure.

[0175] Combined with the following Fig.13 and Fig.14 Two embodiments of sub-step E51 are described.

[0176] In its simplest embodiment (hereinafter also referred to as "first embodiment E51"), as Fig.13 As shown, sub-step E51 consists in winding, around the sealing wall 130 , a plurality of successive sectors 51 of a second strip 5 made of a thermoplastic material sealable by heating and reinforced with fibers.

[0177] The thermoplastic material of the second strip 5 is chemically compatible with the thermoplastic material of the first strip 4 and therefore with the thermoplastic material of the knitted threads 311, 312. It should be noted that the material of the second strip 5 is therefore also compatible with the thermoplastic material of the outer periphery 112a of the bottom 112 or the outer surface of the bottom 112 (in the case where this outer surface is formed by thermoplastic material).

[0178] The second strip 5 is similar to the first strip 4 and may have the same width, or the same type of fibers and / or the same weaving geometry.

[0179] In practice, the sealing wall 130 may be rotatable (eg, by the main shaft 6 ).

[0180] The winding (or wrapping) process of the second strip 5 is similar to that of the first strip 4. Therefore, if Fig.13 As shown, a plurality of successively wound sections 51 of the second strip 5 overlap to form a first layer 510 of the second strip 5. i , i=1, and overlap to form a superposition 50 of the second strip 5. The number n2 of superpositions depends on the size of the tank 1 and can be n2=2 to several hundred, for example n2=200.

[0181] With only the first layer 510 i， The multi-layer winding structure of the second strip 5 enables the impermeability / permeability, mechanical strength and pressure resistance of the reinforced sealing wall 150 (and thus the sealing wall 111 of the tank 1 ) to be improved compared to the winding structure with i=1.

[0182] Each layer 510 of the second strip 5 i , the thickness for i=1 to n2 may for example range from 50 microns to 300 microns. Within a single layer of the second wound strip, the axial overlap distance may for example range from 0 (corresponding to no overlap) to half the width of the second strip 5 .

[0183] As during the winding E22 of the segments 41 of the first strip 4 , during the winding E51 of the second strip 5 , pressure and heat are applied to each winding segment 51 .

[0184] More specifically, the pressure applied to each section 51 of the second winding strip is determined so as to:

[0185] 1) clamping the segment 51 to the outer limit of the sealing wall 130; and

[0186] 2) Clamp the section 51 to the lower layer 510 of the second strip i , i=1 to n2 (during the formation of the superposition of the second strip 5).

[0187] The heating temperature applied to each winding section 51 of the second tape may be the same as the heating temperature applied during winding of the first tape 4. Alternatively, the heating temperature applied to each winding section 51 of the second tape is close to, ie falls within, the melting temperature range of the thermoplastic material used.

[0188] Thus, the thermoplastic material of each wound section 51 of the second strip 5 fuses with the region of the sealing wall 130 situated thereunder and with the underlying layer of the second strip (during formation of the superimposed layers of the second strip).

[0189] After completion of sub-step E51 , the superposition 50 of second strips 5 is joined to the sealing wall 130 so as to form a reinforced sealing wall 150 made of a single material.

[0190] During a sub-step E52 , the second wound strip and the sealing wall 130 are cooled and thus hardened, so as to reinforce and harden said reinforced sealing wall 150 . Said reinforced sealing wall 150 thus forms the sealing wall 111 of the tank 1 .

[0191] Cooling may be carried out after sub-step E51 , ie after the winding of the second strip 5 is completed.

[0192] Alternatively, said cooling may be carried out locally during the winding E51 of the second strip 5 .

[0193] Cooling E52 may be performed in a regulated / regulated manner by injecting cooling water into the interior of the sealing wall 130 , and / or by applying pressure to the inner surface of the sealing wall 130 .

[0194] Fig.14 A preferred embodiment E511 of sub-step E51 is shown. According to this preferred embodiment, sub-step E511 consists in winding a succession of sections 51 of second strip 5 not only around sealing wall 111 , but also on outer surface 112a of bottom 112 .

[0195] After completion of sub-step E511 , the superimposed layer 50 of the second strip 5 thus also overlaps the outer periphery 112 a of the bottom 112 .

[0196] When the outer periphery 112a of the bottom is covered with a thermoplastic material compatible with the thermoplastic material of the sealing wall 111, the superimposed layer 50 of the second strip 5 is bonded to the sealing wall 111 and the outer periphery 112a of the bottom 112. Thus, the reinforced sealing wall 150 (and therefore the sealing wall 111 of the tank 1) extends as far as the circumference of the main axis 6 and is formed from a single material.

[0197] After cooling E521 according to the aforementioned process / method associated with sub-step E52, obtaining Fig.15 The structure shown.

[0198] like Fig.15 As shown, thanks to the preferred embodiment E511, the reinforced sealing wall 150 (and therefore the sealing wall 111 of the tank 1) extends as far as the periphery of the internal passage of the base 112. In other words, the base 112 is partially integrated in the thickness of the sealing wall 111. This makes it possible to prevent pressure rupture around the valve of the tank 1 and thus obtain a tank 1 that is sealed and mechanically resistant to the pressures involved.

[0199] It should be noted that the sealing wall 111 of the tank 1 obtained by implementing the sub-step E511 is advantageously more uniform / homogeneous than the sealing wall obtained according to the first embodiment E51. In fact, the sealing wall 111 is thus formed around its entire periphery by the same reinforced material. This makes it possible to obtain a tank 1 whose sealing wall 111 has the same impermeability and mechanical properties at all positions / points. This (spatial) uniformity of the sealing wall 111 makes it possible to produce a better tank 1.

[0200] Finally, after step E5, the method 100 may comprise a step (not shown in the figures) of applying the valve 122 of the connection 12 of the tank 1 in the internal channel of the bottom 112. Figure 2 The storage tank 1 is shown.

Claims

1. A method (100) for producing a sealing wall (111) of a sealed storage tank (1), the sealed storage tank (1) being designed to contain gas and / or liquid, the method (100) comprising the following steps: - an assembly step (E1): assembling a reusable and removable mandrel (2) by assembling / disassembling a plurality of rings (24), said mandrel (2) having an outer surface (21) whose shape corresponds to the shape of the inner surface of the sealing wall (111) of said tank (1); - Forming step (E2): forming the sealing wall (111) of the storage tank (1) on the outer surface (21) of the mandrel (2), and forming an extraction hole (111d) for extracting the mandrel (2); - a removal step (E3): removing the mandrel (2) from the sealing wall (111) via the extraction hole (111d), The forming step (E2) of forming the sealing wall (111) is performed by performing the following sub-steps: - a forming sub-step (E21): forming the capsule (30) by applying at least one knitted article (3) covering the outer surface (21) of the mandrel (2), the knitted article (3) comprising a layer constituted by knitted threads (311, 312) forming a plurality of loops, the knitted threads (311, 312) being made of a thermoplastic material capable of being sealed by heating; - a winding sub-step (E22) of winding, around the capsule (30) formed by the knitted fabric (3) covering the outer surface (21) of the mandrel (2), a plurality of successive sections (41) of a first strip (4) comprising a thermoplastic material sealable by heating and reinforced with fibers, so that the successive sections (41) of the wound first strip (4) overlap in order to form a first layer (410) of the first strip i , i=1), and overlapping the consecutive sections (41) of the first strip (4) to form a superposition layer (40) of the first strip, the winding sub-step (E22) being performed in the following manner: - applying a selected pressure so as to clamp each section (41) of the wound first strip to the capsule (30) so as to form a first layer (410) of the first strip i , i=1), and in order to clamp a section of the first strip covering the first layer of said first strip to form a further superimposed layer (40) of the first strip, and - applying a temperature selected so as to melt the thermoplastic material of each section (41) of the first layer of the first strip and the knitted threads (131, 132) of the capsule (30) underneath, and so as to melt sections of successive layers of the first strip; - Cooling sub-step (E23): cooling the capsule (30) and the first wound strip (4) so ​​as to form the sealing wall (130) in the form of a single material.

2. The method (100) for producing a sealing wall (111) of a sealed storage tank (1) according to claim 1, wherein: The thermoplastic material of the knitted threads (311, 312) is the same as the thermoplastic material of the first strip.

3. The method (100) for producing a sealing wall (111) of a sealed storage tank (1) according to claim 1 or 2, wherein: The knitted fabric (3) has a thickness of 100 g / m 2 Up to 800g / m 2 The mass per unit surface area within a range of .

4. The method (100) for producing a sealing wall (111) of a sealed storage tank (1) according to any one of claims 1 to 3, wherein: The knitted article (3) is in the form of one or more sleeves, each sleeve being slid onto one end of the spindle.

5. The method (100) for producing a sealing wall (111) of a sealed storage tank (1) according to any one of claims 1 to 4, wherein: The forming sub-step (E21) of forming the capsule (30) also includes applying a second knitted fabric to the first knitted fabric (3), wherein the thermoplastic material of the knitted threads of the second knitted fabric can be sealed by heating under the same temperature and pressure conditions as the thermoplastic material of the knitted threads of the first knitted fabric (3) below.

6. The method (100) for producing a sealing wall (111) of a sealed storage tank (1) according to any one of claims 1 to 5, wherein: The winding sub-step ( E22 ) of winding around said capsule comprises winding at least one other additional strip formed from the material of said first strip, wherein said additional strip is wound simultaneously with said first strip.

7. A method for producing a sealed storage tank for containing gas or liquid, the method comprising the steps of: - producing the sealing wall (130) of the storage tank (1) by performing the assembling step (E1), the forming step (E2) and the removing step (E3) of the method (100) for producing the sealing wall (111) of the sealed storage tank (1) according to any one of claims 1 to 6; - a closing step (E4): closing said sealing wall (130) by applying a base (112) against said sealing wall (130); - a reinforcement step (E5): reinforcing the sealing wall (130) so as to obtain a reinforced sealing wall (150, 111) of the tank (1), The reinforcing step (E5) of reinforcing the sealing wall (130) is performed by executing the following sub-steps: - winding (E51, E511) around the sealing wall (130) a plurality of successive sections (51) of a second strip (5) of thermoplastic material sealable by heating and reinforced with fibers, so that the wound plurality of successive sections (51) of the second strip overlap in order to form a first layer (510) of the second strip (5); i , i=1), and overlapping successive sections (51) of the second strip (5) to form a superimposed layer (50) of the second strip (5), the winding (E51, E511) being performed in the following manner: - applying a selected pressure so as to clamp each section (51) of the wound second strip against the sealing wall (130) so as to form a first layer (510) of the second strip; i , i=1), and so as to clamp a section of the second strip overlapping the first layer of the second strip to form a further superimposed layer of the second strip; as well as - applying a temperature selected so as to melt the thermoplastic material of each section of the first layer of the second strip and the area of ​​the sealing wall (130) below, and so as to melt sections of successive layers of the second strip; - Cooling (E52) the sealing wall (130) and the second strip (5) so as to form a reinforced sealing wall (130, 111) made of a single material.

8. The method (200) for producing a sealed storage tank for containing gas or liquid according to claim 7, wherein: The thermoplastic material of the first strip and the thermoplastic material of the second strip are the same.

9. The method (200) for producing a sealed storage tank for containing gas or liquid according to claim 7 or 8, wherein: The outer peripheral surface of the bottom (112) is covered with a thermoplastic material, which can be sealed by heating and is compatible with the thermoplastic material of the sealing wall (130).

10. The method (200) for producing a sealed storage tank for containing gas or liquid according to any one of claims 7 to 9, wherein: During the reinforcement step (E5) of reinforcing the sealing wall (130), the outer surface of the bottom (112) is covered by the second strip.

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