RU2816298C2 - Method of testing sealed membrane for tightness - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: group of inventions relates to the field of testing devices for tightness and can be used for testing for tightness of sealing membrane (2) attached to heat-insulating barrier (1), which lies on a sealed bearing surface (13). Essence: first strip (17) of sealing mastic is applied on sealing membrane (2). Second strip (18) of sealing mastic is applied on bearing surface (13) around sealing membrane (2). Tight coating (12) is placed on first strip (17) of sealing mastic and on second strip (18) of sealing mastic so that on one side tight coating (12) is tightly connected to sealing membrane (2), and on the other side the tight coating is tightly connected to bearing surface (13). Sealed coating (12) includes a tarpaulin from a polymer film. Tight coating (12), bearing surface (13), first strip (17) of sealing mastic, second strip (18) of sealing mastic and sealing membrane (2) together form closed space (19). Pressure is released in closed space (19) relative to environment outside this space (19). Pressure change inside closed space (19) after depressurisation is measured.

EFFECT: simplified tests.

17 cl, 13 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The invention relates to the field of sealed and thermally insulated membrane tanks. In particular, the invention relates to the field of sealed and thermally insulated tanks for storing and/or transporting liquefied gas at low temperatures, such as tanks for transporting liquefied petroleum gas (LPG), for example, at temperatures from -50°C to 0°C inclusive or for transporting liquefied natural gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank may be designed to transport liquefied gas or to receive liquefied gas to serve as fuel to propel the floating structure.

[0002] In one embodiment, the liquefied gas is LNG, namely a mixture with a high methane content, stored at a temperature of approximately -162°C under atmospheric pressure. Other liquefied gases may also be provided, in particular ethane, propane, butane or ethylene, as well as hydrogen. Liquefied gases can also be stored under pressure, for example at a relative pressure of 0.2 to 2 MPa inclusive, and in particular at a relative pressure close to 0.2 MPa. The reservoir can be constructed using various technologies, in particular in the form of an integrated membrane reservoir.

BACKGROUND OF THE ART

[0003] The sealed and thermally insulated liquefied natural gas storage tank located in the supporting structure has a multi-layer structure, namely, from the outer area towards the inner area of the tank, a auxiliary thermal insulating barrier attached to the supporting structure, an auxiliary sealing membrane that lies on the auxiliary thermal insulation barrier, a main thermal insulation barrier which lies on the auxiliary sealing membrane, and a main sealing membrane which lies on the main thermal insulation barrier and which is intended to be in contact with the liquefied natural gas stored in the tank.

[0004] Document FR2903165 describes a sealed and thermally insulated tank in which prefabricated elements are secured in the interior of a supporting structure to form the tank. Each prefabricated element includes a section of an auxiliary thermal insulating barrier, a section of an auxiliary sealing membrane and a section of a main thermal barrier. These prefabricated elements are attached to the supporting structure according to a grid of regularly shaped cells.

[0005] The main thermal barrier portion of the assembly block only partially covers the secondary sealing membrane. Accordingly, a peripheral portion of the auxiliary sealing membrane of said prefabricated units may be visible. The flexible sealing film is attached to said peripheral portion of the auxiliary sealing membrane of two adjacent prefabricated elements in order to ensure continuity of the auxiliary sealing membrane.

[0006] During construction of the tank, tests are carried out to ensure the tightness of the auxiliary sealing membrane. In some cases, these leak tests must be carried out only on areas of the tank.

[0007] For example, in the context of a small sized tank, such as a fuel supply tank on a ship, the bottom of the tank is first assembled from prefabricated blocks, after which scaffolding is installed to complete the construction of the tank. In this case, it is necessary to test the leak tightness of the auxiliary sealing membrane at the bottom of the tank when the tank has only been partially constructed.

[0008] Also during the construction of the methane tanker tank, the side opening is closed at the end of the tank construction by adding a section of supporting structure on which the tank section is installed. In this case, it is necessary to independently check the tightness of the auxiliary sealing membrane of the added section of the tank.

[0009] However, this type of leak testing of the auxiliary sealing membrane of the reservoir section is complex and requires numerous manipulations and checks. In particular, since this test is carried out only on an unfinished section of the tank, the auxiliary sealing membrane does not form a sealed enclosed space allowing a simple and direct leak test.

[0010] WO2014076424 describes a method for constructing a sealed and thermally insulated tank wall in which welded structures are used to form an enclosed space between an auxiliary sealing membrane and a supporting structure so as to test the auxiliary sealing membrane for leaks. Such welded structures are difficult to implement.

SUMMARY OF THE INVENTION

[0011] One idea behind the invention is to provide a method for testing the tightness of a sealing membrane that is easy to use. In particular, one idea behind the invention is to provide a leak testing method of this type, allowing the sealing membrane of an unfinished portion of a tank to be tested, in other words, a portion of a tank designed to communicate with one or more other portions of the tank in order to complete the construction of the said reservoir. One idea behind the invention is to provide a reliable and rapid leak test.

[0012] To this end, the invention provides a method for testing the tightness of a sealing membrane, wherein the sealing membrane is attached to a thermal barrier and the thermal barrier rests on a sealed support surface, the method comprising the steps of:

- apply the first strip of sealing compound to the sealing membrane;

- apply a second strip of sealing compound to the bearing surface around the sealing membrane;

- place the sealed coating on the first strip of sealed mastic and on the second strip of sealed mastic so that, on the one hand, the sealed coating is hermetically connected to the sealing membrane using the first strip of sealed mastic, and, on the other hand, the sealed coating is sealed with the load-bearing surface using a second strip of sealing compound, wherein the sealing cover, the supporting surface, the first strip of sealing compound, the second strip of sealing compound and the sealing membrane together form an enclosed space;

- releasing the pressure in the enclosed space relative to the environment outside said enclosed space; And

- measuring a parameter representing the change in pressure inside the enclosed space after the pressure in said enclosed space has been released.

[0013] Thanks to these features, it is possible to test the tightness of the sealing membrane of a tank section during the construction phase in a simple and reliable manner. In particular, by applying strips of sealing compound and positioning the sealing coating in a sealed manner on the sealing membrane and on the supporting surface by means of strips of sealing compound, it is possible to simply and quickly create an enclosed space without the need for complex manipulation. In particular, this enclosed space is obtained without the need to weld metal parts to the sealing membrane and/or to the supporting surface.

[0014] Embodiments of this type of leak testing method may have one or more of the following features.

[0015] The strip of sealing compound can have various shapes. It is preferably made in the form of a roll which is unwound to apply a strip of sealing compound to the desired surface, but could equally, for example, be made from cartridges used with a sealing compound gun, or be made from lump material. This type of sealing compound strip is elongated and is applied to surround the area of the sealing membrane that is to be tested for leaks.

[0016] In accordance with one embodiment, the strip of sealing compound is, for example, an adhesive tape. In accordance with one embodiment, the first strip of sealing compound and/or the second strip of sealing compound includes a film and a layer of sealing compound on one surface of said film. According to one embodiment, the sealing compound layer is a layer of rubber, preferably a layer of synthetic rubber. According to one embodiment, the layer of sealing compound has a thickness of from 1 to 4 mm inclusive, for example 3 mm. In accordance with one embodiment, the first strip of sealing compound and/or the second strip of sealing compound is or are made by applying layers of sealing compound.

[0017] In accordance with one embodiment, the sealant strip is a butyl sealant strip, in other words, a plastic polyisobutylene-based sealant.

[0018] The rigid secondary barrier (RSB) or Triplex® preferably has a shear strength, determined at -170°C in accordance with ISO4587, from 17 to 30 MPa, inclusive, and preferably greater than 22 MPa.

[0019] In one embodiment, the sealant strip is a strip of adhesive sealant, e.g., sealant applied using a sealant gun or any other device capable of applying a bead of sealant having the required length dimensions, thickness, section, etc. According to one embodiment, the first strip of sealing compound and/or the second strip of sealing compound is made or formed from a bead of sealing compound having a thickness of from 1 mm to 15 mm inclusive, preferably from 2 mm to 10 mm inclusive. A bead of this type of sealing compound preferably eliminates defects in the flatness of the load-bearing surface.

[0020] According to one embodiment, a first strip of sealing compound is secured to a peripheral portion of the sealing membrane, said peripheral portion of the sealing membrane surrounding a central portion of the sealing membrane that is to be leak tested.

[0021] In accordance with one embodiment, the sealing membrane includes at least one portion of a composite seal film, the method further including applying an adhesive layer to the surface of the at least one portion of the composite film such that said adhesive layer is absorbed into a portion of the composite film, wherein a first strip of sealing compound is applied to said surface of said at least one portion of the composite film.

[0022] An adhesive layer of this type impregnating a portion of the composite seal film provides good interaction between the first strip of sealing compound and the sealing membrane, including at the level of the portion of the composite seal film, in particular when the composite seal film is a flexible composite film, as described below. In fact, this type of composite seal film may have irregularities, for example due to the presence of visible fibers. These irregularities can impair the sealing interaction between the first strip of sealing compound and the sealing membrane at the level of the composite sealing film. Accordingly, this type of adhesive layer, absorbed into the composite seal film, adheres satisfactorily to the portion of the composite seal film while offering a satisfactory area of adhesion and interaction with the first strip of seal compound. This is of particular interest when a portion of the sealed flexible composite film includes layers of non-resin glass fiber to which the first strip of sealant compound does not adhere properly.

[0023] In accordance with one embodiment, the adhesive layer is a layer of polyurethane adhesive.

[0024] In accordance with one embodiment, the first strip of sealing compound is adhesive. In accordance with one embodiment, the second strip of sealing compound is adhesive.

[0025] Strips of this type of adhesive sealing compound facilitate the leak testing method. In fact, strips of adhesive sealing compound of this type provide a simple and reliable sealing connection between said strips of adhesive sealing compound and, on the one hand, the sealing membrane or support surface, and, on the other hand, the sealing coating. In addition, strips of this type of adhesive sealing compound can be attached quickly and securely to the sealing membrane as well as to the load-bearing surface.

[0026] In one embodiment, the first strip of sealing compound is made of synthetic rubber. According to one embodiment, the second strip of sealing compound is made of synthetic rubber.

[0027] In accordance with one embodiment, the sealing cover is a canvas made of a polymer film.

[0028] In accordance with one embodiment, the polymer film tarpaulin is made from a material selected from vinyl, nylon and polyethylene.

[0029] This type of polymer film tarpaulin is simple and quick to manufacture and shape to size to form an airtight cover. Moreover, this type of polymer film tarpaulin is easy to install and still offers satisfactory sealing and strength properties when relieving pressure in a confined space.

[0030] In accordance with one embodiment, the method further includes the step of providing a screen covering the gap between the thermal barrier and the load-bearing surface to prevent the polymer film canvas from being positioned in said gap during depressurization of the enclosed space. .

[0031] This type of screen makes it possible to bridge the gap between the thermal insulating barrier and the load-bearing surface. In fact, in the context of a tank embedded in a supporting structure, such as a double hull, mastic beads are typically placed between the thermal barrier and the load-bearing surface formed by the inner hull of the ship in order to eliminate flatness defects in the supporting structure. In this regard, a gap may separate the thermal insulating barrier from the load-bearing surface. This type of screen helps prevent the plastic film tarp from being damaged when inserted into the space during the release of pressure in a confined space.

[0032] In accordance with one embodiment, the screen is a plate of, for example, a plastic material.

[0033] According to one embodiment, the method includes positioning a protective angle steel including a first flat flange and a second flat flange such that the first flat flange is positioned on the sealing membrane and the second flat flange extends along edges of the heat-insulating barrier and protrudes towards the load-bearing surface.

[0034] In accordance with one embodiment, the screen extends in the direction of the tank wall thickness, towards the interior region of the tank beyond the edge of the second flat flange of the protective angle steel. This prevents the polymer film tarpaulin from coming into contact with the insulating pad of the thermal barrier.

[0035] In accordance with one embodiment, the screen includes a steel angle resting on one side on the thermal barrier and on the other side on the load-bearing surface so as to form a flat supporting surface between the thermal barrier and the load-bearing surface, wherein a second strip of sealing compound is applied to the supporting surface so as to surround the steel angle such that said steel angle is placed in an enclosed space, wherein the polymer film canvas is caused to abut against said flat supporting surface during the release of pressure in said enclosed space.

[0036] In one embodiment, a reinforcing fabric is attached to a polymer film tarpaulin, the tarpaulin being attached such that the reinforcing fabric is located in a confined space at the level of the corner formed by the thermal barrier.

[0037] This type of reinforcing fabric helps prevent damage to the polymer film tarpaulin during pressure release in a confined space. In fact, this type of polymer film canvas is relatively thin and can be damaged during confined space depressurization, said confined space depressurization bringing the polymer film canvas into contact with the raised corners formed by the thermal barrier. In addition, the side surface of the thermal barrier may have some roughness, for example, if the side surface of the thermal barrier is formed by an insulating liner including reinforcing fibers. This roughness can also damage the plastic film tarpaulin during pressure release in a confined space. Because of this, this reinforcing fabric provides protection to the polymer film tarpaulin during pressure relief in a confined space.

[0038] According to one embodiment, the thermal barrier includes a plurality of prefabricated blocks arranged side by side in a regular pattern. According to one embodiment, the sealing membrane includes a plurality of rigid seal film sections, with each rigid seal film section being embedded in a corresponding assembly block. According to one embodiment, a section of rigid seal film, and preferably each section of rigid seal film, includes a sheet of aluminum disposed between two layers of fiberglass and resin, this type of rigid seal film being sold particularly under the product name "rigid Triplex®" . In accordance with one embodiment, the sealing membrane includes one or more sections of flexible and composite sealing film. In accordance with one embodiment, said section or sections of the flexible composite film are sealed or attached, for example glued, to the rigid sealed film sections of two adjacent prefabricated units. In accordance with one embodiment, the section or sections of flexible composite film include(s) a sheet of aluminum disposed between two layers of non-resin glass fiber, wherein a section of this type of flexible composite film is sold particularly under the product name "flexible Triplex®". According to one embodiment, the portion of the composite seal film to which the adhesive layer is applied is a portion of a flexible composite film.

[0039] In accordance with one embodiment, a first strip of sealing compound is applied to the sealing membrane after the sealing membrane has been attached to the thermal barrier.

[0040] In accordance with one embodiment, the first strip of sealing compound is applied directly to the rigid sealing film.

[0041] In accordance with one embodiment, the first strip of sealing compound is applied indirectly through an adhesive layer to a flexible sealing film.

[0042] In accordance with one embodiment, the method further includes the steps of removing the sealant cover, removing the first strip of sealing compound, and removing the second strip of sealing compound after the step of measuring a parameter representing the change in pressure in the enclosed space. In accordance with one embodiment, the method further includes the step of stripping the adhesive layer. This stripping of the adhesive layer ensures that any contamination resulting from the application of the adhesive layer to the sealing membrane is removed.

[0043] In accordance with one embodiment, the sealed enclosure includes a sealed metal structure.

[0044] This type of metal structure offers good reliability during leak testing while providing simple and rapid sealing of a confined space by positioning said metal structure on strips of sealing compound. In addition, this type of metal structure is weighted to seal against the strips of sealing compound in a simple and effective manner.

[0045] According to one embodiment, the metal structure includes:

- central area,

- flat inner edge and

- flat outer edge,

and the flat inner edge extends in a first plane parallel to the sealing membrane, and the flat outer edge extends in a second plane parallel to the load-bearing surface,

and the sealing cover is positioned such that a first strip of sealing compound is sealed between the flat inner edge and the sealing membrane, and such that a second strip of sealing compound is sealed between the flat outer edge and the load-bearing surface.

[0046] In accordance with one embodiment, the metal structure is made of stainless steel.

[0047] In accordance with one embodiment, the central portion is flat. According to one embodiment, the central portion extends in a plane parallel to the direction of the thickness of the tank wall.

[0048] In accordance with one embodiment, the inner edge extends in a first plane and the outer edge extends in a second plane, the first plane and the second plane forming an angle corresponding to the angle between the sealing membrane and the supporting surface.

[0049] In accordance with one embodiment, the flat inner edge extends perpendicular to the flat central portion. According to one embodiment, the flat outer edge extends perpendicular to the flat central portion. According to one embodiment, a flat inner edge extends from a first edge of a flat center portion of a first side of said flat center portion, and a flat outer edge extends from a second edge of a flat center portion of a second side of a flat center portion, the first edge of the flat center portion being opposite the second edge of the flat center portion. the central portion, and the first side of the flat central portion is opposite to the second side of the flat central portion.

[0050] In accordance with one embodiment, a plurality of the aforementioned metal structures are positioned between the sealing membrane and the supporting surface, with additional strips of sealing compound being sealed between two successive metal seal structures.

[0051] According to one embodiment, the metal structure includes an inner portion and an outer portion, the inner portion including a flat inner edge and a first central portion portion, and the outer portion including a flat outer edge and a second central portion portion,

and the stage of arranging the sealed covering includes the stages of:

- position the first part of the metal structure so that the flat inner edge lies on the first strip of sealing compound,

- position the second part of the metal structure so that the flat outer edge lies on the second strip of sealing compound, and

- hermetically connect the first part of the metal structure and the second part of the metal structure.

[0052] A two-piece metal structure of this type preferably eliminates inconsistencies associated with manufacturing tolerances of the tank section and/or parts of the metal structure. In particular, the first portion and the second portion of the central portion may overlap to a greater or lesser extent to form the central portion and thereby eliminate inconsistencies resulting from manufacturing tolerances of the metal structure or thermal barrier, or again from defects in the flatness of the load-bearing surface.

[0053] The first metal structure portion and the second metal structure portion may be sealed in numerous ways. In accordance with one embodiment, the first metal structure portion and the second metal structure portion are sealed together by welding. In accordance with one embodiment, the first metal structure portion and the second metal structure portion are sealed together using a strip of sealing compound.

[0054] In accordance with one embodiment, the method further includes the step of applying a support reaction force in the direction of the load-bearing surface to the sealant cover in line with the first strip of sealing compound and in line with the second strip of sealing compound.

[0055] Applying this type of support reaction force to the sealing liner in line with the sealing compound strip provides good interaction and good sealing between the sealing cover and the sealing membrane and/or support surface.

[0056] In accordance with one embodiment, the method further includes the step of attaching a cover sheet at the level of a corner of the thermal barrier such that said cover sheet covers said corner, wherein the cover sheet is sealed on one side to the load-bearing surface, and, on the other hand, with an auxiliary sealing membrane.

[0057] In accordance with one embodiment, the sealant includes a cover sheet. In accordance with one embodiment, the cover sheet is placed in a confined space.

[0058] In accordance with one embodiment, the cover sheet is a metal part, for example, a stainless steel part. The cover sheet can be attached in numerous ways to the sealing membrane or to the supporting surface. According to one embodiment, the cover sheet is welded to the supporting surface. According to one embodiment, the cover sheet is sealably connected to the supporting surface and/or to the sealing membrane by means of a strip of sealing compound, such as a first strip of sealing compound and/or a second strip of sealing compound, respectively.

[0059] In accordance with one embodiment, the corner covered by the cover sheet is a protruding corner of the thermal barrier.

[0060] According to one embodiment, the corner has an edge that extends in the thickness direction of the reservoir, the cover sheet has a first flat flange covering a portion of a first side surface of the thermal barrier, and a second flat flange covering a portion of a second side surface of the thermal barrier, said portions of the first side surface and the second side surface of the heat-insulating barrier form the mentioned corner of the heat-insulating barrier. In accordance with one embodiment, the cover sheet includes a third flange that extends in a plane perpendicular to the thickness direction of the container, said third flange being sealed to the sealing membrane.

[0061] In one embodiment, the cover sheet is produced by molding it in place at a corner of the thermal barrier.

[0062] In accordance with one embodiment, the method includes the step of positioning a connecting device comprising a connecting angle steel and a connecting flange disposed opposite an opening formed in said connecting angle steel, wherein said connecting angle steel is sealedly connected to a load-bearing surface , with a sealing membrane and with a sealed cover, and the connecting flange is sealed with the pressure relief means in the enclosed space.

[0063] In accordance with one embodiment, the connecting angle steel is manufactured by molding it in place on a thermal barrier, with the connecting flange being embedded into the body of the connecting steel angle during its formation.

[0064] In accordance with one embodiment, the invention also provides a sealing device for closing an enclosed space formed between a sealing membrane attached to a thermal barrier attached to a load-bearing surface and said load-bearing surface, the sealing device including:

- a sealed covering, hermetically connected, on the one hand, to the sealing membrane by means of a first strip of sealing compound, and, on the other hand, to the load-bearing surface by means of a second strip of sealing compound, and

- a vacuum pump connected to the enclosed space and capable of relieving pressure in said enclosed space.

[0065] This type of sealing device provides a simple, fast and reliable leak test of a section of a tank.

[0066] Embodiments of this type of sealing device may have one or more of the above-mentioned features or the following features.

[0067] In accordance with one embodiment, the sealing cover includes a plastic film canvas, wherein the sealing device further includes a screen covering the gap between the thermal insulating barrier and the load-bearing surface so as to bridge the gap and prevent insertion of the polymer film canvas during the mentioned period under pressure release conditions in a confined space.

[0068] In accordance with one embodiment, the sealing device further includes a pressing device configured to apply a support reaction force in the direction of the load-bearing surface to the sealant cover in line with the first and second strips of sealing compound.

[0069] Applying this type of support reaction force to the sealant liner in line with the sealant compound strips provides good interaction and good sealing of the sealant cover to the sealant compound strips.

[0070] In accordance with one embodiment, the clamping device includes a fastening element attached to the support surface and a support plate, the support plate being movably mounted in a thickness direction of the reservoir on the fastening element so that it can abut against the sealing cover in line with the second strip of sealing compound.

[0071] In accordance with one embodiment, the prefabricated units include a portion of a primary thermal barrier resting on a rigid sealed film. According to one embodiment, said portions of the thermal barrier are sized smaller than the dimensions of the rigid seal film such that the periphery of said rigid seal film is visible.

[0072] In accordance with one embodiment, the clamping device includes a support member attached to a portion of the main thermal barrier of the assembly block.

[0073] According to one embodiment, the sealing membrane is a corrugated sealing membrane including a first parallel corrugation sequence and a second parallel corrugation sequence, wherein the corrugations of the first parallel corrugation sequence and the corrugations of the second parallel corrugation sequence intersect, and the sealing membrane includes a set of nodes formed at the level of intersections between the corrugations of the first row of parallel corrugations and the corrugations of the second row of parallel corrugations. In accordance with one embodiment, the clamping device includes a support element attached to the sealing membrane, for example, by snapping it onto the undercuts formed by the sealing membrane assemblies.

[0074] In accordance with one embodiment, said support element has a base attached to said portion of the primary thermal barrier, for example, one of said sealing membrane assemblies, a spacer element that extends from said base in the direction of the rigid sealing film, and a support plate movably mounted in a thickness direction of the reservoir on the spacer member so as to be capable of applying a support reaction force to the sealed cover in line with the first strip of sealing compound.

[0075] In accordance with one embodiment, the load-bearing surface is formed by a load-bearing structure designed to receive a sealed and thermally insulated tank including a sealing membrane, the tightness of which is required to be tested, for example, by the inner hull of a vessel including said tank.

[0076] According to one embodiment, the support surface is formed by a secondary sealing membrane of a sealed and thermally insulated container, the sealing membrane to be tested in this case being the main sealing membrane.

[0077] A leak test method of the above-mentioned type or a sealing device of the above-mentioned type may be used in a tank, which may be part of a land-based storage facility, such as LNG storage, or which may be installed in a coastal water floating structure or a deep-sea floating structure. structures, in particular on a methane tanker, floating storage and regasification unit (FSRU), floating production, storage and offloading unit (FPSO), etc. This type of tank can also serve as a fuel tank on any type of vessel.

BRIEF DESCRIPTION OF THE FIGURES

[0078] The invention will be better understood and other objects, details, features and advantages thereof will become more apparent through the following description of many separate embodiments of the invention, given by way of non-limiting illustration only and with reference to the accompanying drawings.

[0079] FIG. 1 is a schematic perspective view of a section of a sealed and thermally insulated tank.

[0080] FIG. 2 is a cross-sectional view of a portion of the sealed and thermally insulated tank of FIG. 1, in which the sealing device according to the first embodiment is installed.

[0081] FIG. 3 is a cross-sectional view of a portion of the sealed and thermally insulated tank of FIG. 1, on which a sealing device according to the first embodiment of the first embodiment illustrated in FIG. 2.

[0082] FIG. 4 is a sectional view of a portion of the sealed and insulated tank of FIG. 1, on which a sealing device according to the second embodiment of the first embodiment illustrated in FIG. 2.

[0083] FIG. 5 is a schematic perspective view of a section of a sealed and thermally insulated container whose sealing membrane is to be leak tested.

[0084] FIG. 6 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, during the first step of implementing the leak testing method by means of a sealing device according to the second embodiment.

[0085] FIG. 7 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, during the second step of implementing the leak testing method by means of a sealing device according to the second embodiment.

[0086] FIG. 8 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, during the third step of implementing the leak testing method by means of a sealing device according to the second embodiment.

[0087] FIG. 9 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, during the fourth step of implementing the leak testing method by means of a sealing device according to the second embodiment.

[0088] FIG. 10 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, during the fifth step of implementing the leak testing method by the sealing device according to the second embodiment.

[0089] FIG. 11 is a schematic detailed perspective view of the portion of the tank illustrated in FIG. 5, on which the sealing device according to the second embodiment is installed.

[0090] FIG. 12 is a sectional view of a portion of the sealed and insulated tank of FIG. 1, on which a sealing device according to another embodiment of the first embodiment illustrated in FIG. 2.

[0091] FIG. 13 is a perspective view of the connecting device during its production by molding it in place onto an auxiliary thermal barrier.

DESCRIPTION OF IMPLEMENTATION OPTIONS

[0092] Throughout the remainder of the description, the terms "external" and "internal" will be used to refer, as defined herein, to the relative position of one element relative to another with respect to the interior of the reservoir. Thus, an element close to or facing the internal region of the reservoir is described as internal, as opposed to an external element located close to or facing the external region of the reservoir.

[0093] In FIG. 1 shows a section of a sealed and thermally insulated tank mounted on a supporting structure 13. A section of a tank of this type includes, from the outer area of the tank towards the inner area of the tank, an auxiliary thermal insulating barrier 1, an auxiliary sealing membrane 2, a main thermal insulating barrier 3 and a main sealing membrane membrane (not illustrated in Fig. 1).

[0094] The reservoir is constructed from prefabricated blocks 4, each of which includes a section of an auxiliary thermal insulating barrier, a section of an auxiliary sealing membrane and a section of a main thermal barrier. Specifically, each assembly unit 4 includes, from the outer region of the tank to the inner region of the tank, a bottom plate 5, an auxiliary insulation pad 6, a rigid sealing film 7, a main insulation pad 8, and a cover plate 9. The bottom plate 5 and the auxiliary the insulating pad 6 forms a first substantially parallelepiped-shaped block covered by the rigid sealing film 7, and the main insulating pad 8 and the cover plate 9 form a second substantially parallelepiped-shaped block lying on the rigid sealing film 7.

[0095] The bottom plate 5 and the cover plate 9 are made of plywood, for example. The auxiliary insulating pad 6 and the main insulating pad 8 are made, for example, of polyurethane foam, which can be reinforced with fibers. The rigid sealing film 7 is made, for example, of rigid Triplex®, in other words, consisting of a sheet of aluminum sandwiched between two layers of fiberglass and resin.

[0096] In this type of assembly unit 4, the bottom plate 5, the auxiliary insulating pad 6 and the rigid sealing film 7 have dimensions in a plane perpendicular to the thickness direction of the tank larger than the dimensions of the main insulating pad 8 and the cover plate 9, so that the peripheral boundary 10 is rigid sealed film is not covered with the main insulating gasket 8.

[0097] During the construction of a tank, prefabricated blocks 4 of this type are attached to a supporting structure 13, for example, the inner wall of a double hull of a ship, in a side-by-side manner. The flexible seal film 11 is applied to the peripheral boundary 10 of the rigid seal film 7 of two adjacent prefabricated units 4 so as to provide continuity of sealing between the rigid seal films 7 of two adjacent prefabricated units 4. This flexible seal film 11 is made, for example, of flexible Triplex® , in other words, consists of a sheet of aluminum between two layers of fiberglass without resin. The auxiliary sealing membrane 2 is formed by a rigid sealing film 7 of these two prefabricated units 4 and a flexible sealing film portion 11 connecting the adjacent peripheral boundary portions 10 of the two prefabricated units 4. Other details of this type of prefabricated units 4, their arrangement or also other constituent elements of the tank are described eg in document FR2903165.

[0098] During the construction of tanks, it is necessary to test the tightness of the auxiliary sealing membrane 2 under construction.

[0099] This is, for example, the case in small sized tanks, such as tanks intended to serve as fuel tanks supplying a propulsion system. In fact, these tanks are most likely assembled in two stages, with the bottom of the tank first being installed on the support structure 13, followed by a second period of time and after the scaffolding has been installed, the top of the tank is installed on the support structure 13. The auxiliary sealing membrane must be tested for leaks 2 before installing the top of the tank. Now that only the lower part of the tank has been assembled, the auxiliary sealing membrane 2 is only partially formed and the peripheral boundary 10 can be seen on the prefabricated blocks that form the edges of said lower part of the tank.

[0100] This also applies to tank closure in the context of a methane tanker tank. In fact, during the construction of the tank of a methane tanker, a side section of the supporting structure 13 and therefore the corresponding tank remains open in order to allow the passage of the tools necessary for the construction of the tank. This opening, commonly referred to as a skin opening, is closed to complete the construction of the tank by installing a section of supporting structure 13 on which a corresponding section of the tank is installed. The tank section installed on the added support structure section 13 includes prefabricated blocks 4 and has a visible peripheral boundary 10 of the auxiliary seal membrane 2. The tightness of the auxiliary seal membrane 2 formed by this assembled tank section must also be tested before completion of the tank construction.

[0101] The leak test device is made to test the leak tightness of the auxiliary sealing membrane 2 in the tank during the construction stage. Figures 2-4 illustrate a first embodiment of a leak test apparatus of this type.

[0102] In the example illustrated in FIG. 1, only two assemblies 4 are illustrated. The remainder of the description of this first embodiment of the leak test apparatus is given in the context of the tank portion formed by the two assemblies 4 and the flexible sealing film portion 11 connecting said assemblies 4. However, this description is applicable to analogies to any assembly of prefabricated blocks 4 attached to the supporting structure and connected at the level of their adjacent edges by sections of flexible sealed film 11.

[0103] A portion of this type of tank includes a central portion 14 of an auxiliary sealing membrane 2 that must be leak tested. The central section 14 is formed by rigid sealed films 7 of adjacent prefabricated blocks 4 and sections of flexible sealed film 11 connecting said prefabricated blocks 4. The central section 14 is surrounded by a peripheral section 15 of an auxiliary sealing membrane 2. This peripheral section 15 is formed, on the one hand, by sections 10 of a peripheral boundaries located at the surface level of the prefabricated blocks 4 without the prefabricated block 4 facing them, and, on the other hand, by the outermost sections 16 of the sections 11 of the flexible sealed film connecting the mentioned sections 10 of the peripheral boundary.

[0104] In FIG. 2 illustrates a sectional view of a portion of a tank at a construction stage on which a leak-tightness test apparatus for an auxiliary sealing membrane is installed according to the first embodiment. In this fig. 2 generally illustrates a sectional view of the prefabricated blocks 4 at the level of the section plane A-A in FIG. 1. The function of this leak test device is to provide a leak test of the central portion 14 of the auxiliary sealing membrane 2 formed by the two prefabricated blocks 4 and the flexible sealing film portion 11 sealingly connecting the mutually facing portions of the peripheral boundaries 10 of the two prefabricated blocks 4.

[0105] According to this first embodiment, the leak testing apparatus includes a resin film tarpaulin 12 sealed on one side to an auxiliary sealing membrane 2 and on the other hand to a supporting structure 13 by means of strips of sealing compound .

[0106] The first strip of adhesive sealing compound 17 is applied to the rigid sealing film 7. Specifically, this first strip of adhesive sealing compound 17 is sealingly applied to the peripheral portion 15 of the sealing membrane 2, in other words, to the entire periphery of the auxiliary sealing membrane 2, completely surrounding the central section 14 of the auxiliary sealing membrane 2 to be tested.

[0107] A second strip of adhesive sealing compound 18 is applied directly to the supporting structure 13. Specifically, this second strip of adhesive sealing compound 18 is sealed onto the supporting structure 13 so as to completely surround the portion of the tank whose auxiliary sealing membrane 2 is to be tested for tightness.

[0108] The polymer film tarpaulin 12 is sealed onto the first strip of adhesive sealing compound 17. Likewise, the polymer film tarpaulin 12 is sealed onto the second strip of the adhesive sealing compound 18. The polymer film tarpaulin 12 seals the auxiliary sealing membrane 2 coated with the first strip of sealant compound 17, and the supporting structure 13 at the level of the second strip of sealing compound 18. As a result, the enclosed space 19 is limited jointly by the section 20 of the supporting structure 13, surrounded by the second strip of sealing compound 18, the tarpaulin 12 of the polymer film and the central section 14 of the auxiliary sealing membrane 2, surrounded by first strip of sealing compound 17.

[0109] The first strip of sealing compound 17 and the second strip of sealing compound 18 are preferably made of synthetic rubber. For example, the strips of sealing compound 17, 18 take the form of strips of adhesive sealing compound having a thickness of adhesive synthetic rubber from 1 to 4 mm inclusive, for example 3 mm, supported by a polyester PTFE (polytetrafluoroethylene) or other film, the strip being unwound when applied to a surface having sealant onto the application surface, and the film is removed once the sealant has been applied to said surface. Synthetic rubber adhesive strips 17, 18 of this type are produced, for example, by Airtech®, for example under the product name AT-200Y. The sealant composition is, for example, a butyl sealant composition, in other words, a plastic sealant composition based on polyisobutylene. A sealing composition of this type has a viscosity at rest and at 25°C from 735,000 to 805,000 Pa s inclusive, for example about 770,000 Pa s, and a viscosity at 25°C from 180,000 to 250,000 Pa s inclusive, for example about 215,000 Pa s when it is loaded with a shear rate of 0.6 s ^-1 . Moreover, a sealing composition of this type has a shear strength, determined at -170°C in accordance with the ISO4587 standard, from 17 to 30 MPa inclusive and preferably above 22 MPa. Finally, this type of sealant has been found to have excellent adhesive properties.

[0110] The polymer film tarpaulin 12 is made, for example, from vinyl film or nylon, such as the tarpaulin manufactured by Airtech® under the product name Wrightlon®. A nylon tarpaulin of this type has, for example, a thickness of from 50 to 100 µm inclusive, for example of the order of 70 µm. According to another embodiment, the polymer film tarpaulin 12 is made of polyethylene and preferably has a thickness of from 150 to 240 microns inclusive, for example about 190 microns. A polymer film tarpaulin 12 of this type is airtight and can be securely and easily sealed by means of a strip of adhesive sealing compound 17, 18 such as those described above. Moreover, the tarpaulin 12 of this type of polymer film can be easily changed in size depending on the size of the area of the tank, the auxiliary sealing membrane 2 of which must be tested for leaks.

[0111] To check the tightness of the fastening of the first strip of sealing compound 17 to the auxiliary sealing membrane 2, the second strip of sealing compound 18 to the supporting structure 13 and the tarpaulin 12 of the polymer film to the mentioned strips of adhesive sealing compound 17, 18, you can, for example, use an acoustic detection system leak detection system, such as an ultrasonic leak detection system, after the first depressurization of the confined space 19. One such ultrasonic leak detection system is, for example, the VacleakLEQ-70® system manufactured by Airtech®.

[0112] In order to test the tightness of the auxiliary sealing membrane 2 to be tested, in other words, the central portion 14 surrounded by the first strip of sealing compound 17, the resin film tarpaulin 12 is connected to the pressure relief means. One such pressure relief means is, for example, a vacuum pump 31 connected to the enclosed space 19, or any other pressure relief means capable of reducing the pressure in the enclosed space 19.

[0113] Actuation of the pressure relief means allows the pressure in the enclosed space 19 to be reduced relative to the environment external to said enclosed space 19. This pressure relief is, for example, from -0.05 MPa to -0.06 MPa.

[0114] In order to detect any defect in the sealing of the auxiliary sealing membrane 2, the change in a parameter representing the pressure in the enclosed space 19 is then monitored by a special sensor, for example, a sensor built into the vacuum pump 31. This parameter may, for example, be the pressure measured in a confined space by the pressure sensor 32, the tension parameter of the polymer film tarpaulin 12 under pressure release conditions in the confined space 19, an acoustic parameter or any other parameter that provides a measurement of the pressure change in the confined space 19. Defect in the tightness of the auxiliary sealing membrane 2 under conditions test is detected in the event of an increase in pressure in the enclosed space 19 relative to the environment external to said enclosed space 19.

[0115] The flexible seal film portion 11 has a higher roughness than the rigid seal film portion 7. In fact, the Triplex® flexible seal film portion 11 includes visible fibers that impair the seal adhesion of the first strip of adhesive sealing compound 17 to said flexible seal film portion 11.

[0116] In order to provide a sealed interaction between the flexible seal film portion 11 and the first strip of sealing compound 17, a layer of polyurethane adhesive 21 is applied to the outermost portions 16 of the flexible seal film portion 11 designed to receive the first strip of sealing compound 17. This layer of polyurethane adhesive 21 penetrates into the flexible seal film portion 11, thereby ensuring good interaction between said polyurethane adhesive layer 21 and the flexible seal film portion 11. In addition, this layer of polyurethane adhesive 21 offers a good adhesive surface for the first strip of sealing compound 17, thereby ensuring that said first strip of sealing compound 17 is sealed and securely attached to the portion of the flexible sealing film 11. In order to ensure good absorption of the polyurethane layer 21 in flexible sealing film 11, a layer of polyurethane adhesive 21 is preferably heated and pressed. Following the leak test, the polyurethane adhesive layer 21 is preferably scraped off to prevent any polyurethane adhesive residue from remaining on the portion of the flexible seal film 11. Likewise, the leak test is preferably followed by an inspection, such as a simple visual inspection by a worker, to ensure that there is no residue on the first strip of sealing compound. 17 and, where applicable, a second strip of sealing compound 18.

[0117] In FIG. 3 illustrates a first embodiment of a first embodiment of a leak test apparatus. This first embodiment differs from the embodiment described with reference to FIG. 2, in that the leak testing device additionally includes a steel angle 22 forming a screen and a reinforcing fabric 23.

[0118] When the pressure is released in the enclosed space 19, the resin film canvas 12 comes into contact with and is pressed against the auxiliary thermal insulating barrier 1 as a result of the pressure release. In particular, the resin film canvas 12 is brought into contact with the raised corner formed by the auxiliary thermal insulating barrier 1. The relatively thin resin film tarpaulin 12 may therefore be damaged in contact with the raised corner formed by the auxiliary thermal insulating barrier 1.

[0119] In this first embodiment, the reinforcing fabric 23 is arranged to cover the raised corner formed by the auxiliary insulating barrier 1 and thereby protect the polymer film canvas 12 when the enclosed space 19 is depressurized.

[0120] Likewise, the insulating pad 6 of the auxiliary thermal insulating barrier 1 may have a large roughness, particularly when the insulating pad 6 is formed from fiber-reinforced foam. This roughness of the insulating liner 6 can also damage the resin film tarpaulin 12 when the pressure in the confined space 19 is depressurized, said depressurization of the enclosed space bringing the resin film tarpaulin into contact with the auxiliary insulation pad 6. In this regard, the reinforcing fabric 23 is preferably covers the side surfaces of the prefabricated blocks 4 so as to protect the polymer film tarpaulin 12 when the pressure in the enclosed space 19 is released.

[0121] Reinforcing fabric 23 of this type is installed, for example, attached to or located on the auxiliary thermal insulating barrier 1 in places that can damage the polymer film tarpaulin 12. This reinforcing fabric may equally be incorporated directly into the polymer film canvas 12, for example by gluing it thereto, and the polymer film canvas is then secured to form an enclosed space such that this reinforcing fabric 23 is located at the desired locations of the auxiliary thermal insulation barrier 1 when pressure is released in confined space 19. This type of reinforcing fabric 23 can be made from numerous materials, such as cardboard, wood, plastic, etc., to provide protection to the polymer film tarpaulin 12.

[0122] In addition, when the prefabricated blocks 4 are attached to the supporting structure 13, a gap 24 remains between the bottom plate 5 of the prefabricated blocks 4 and the supporting structure 13. This gap is the result of the presence of beads of sealing compound between the bottom plate 5 of the prefabricated blocks 4 and the supporting structure 13. Beads of this type of sealing compound provide relief from flatness defects in the supporting structure 13 and offer a flat supporting surface for securing the prefabricated units 4.

[0123] An angle steel 22 is installed around the portion of the tank whose auxiliary sealing membrane 2 is to be tested for leaks. An angle steel 22 is positioned along the secondary thermal barrier 1 so as to bridge the gap separating the prefabricated units 4 and the support structure 13. This angle steel 22 typically has a flat plate that extends from the support structure 13 towards the interior of the tank to at least bottom plate 5 of the prefabricated blocks 4. Therefore, this flat plate offers a continuous and flat bearing surface around the portion of the tank whose auxiliary sealing membrane 2 must be tested for leaks. When pressure is released in the enclosed space 19, the plastic film tarpaulin 12 as a result of the depressurization in the enclosed space 19 rests against this flat surface formed by the steel angle 22 and cannot be inserted into the spaces separating the prefabricated blocks 4 and the supporting structure 13 because such an insert can damage the tarpaulin 12 made of polymer film.

[0124] In a similar manner, which is not shown, overlap means may be provided between two side surfaces of adjacent prefabricated units 4 to prevent damage to the polymer film canvas 12 as a result of a decrease in pressure in the enclosed space 19. This overlap means is formed, for example, by covering the spaces between adjacent prefabricated blocks 4 with reinforcing fabric 23, a flat plate or any other suitable means. In this regard, this overlap means can also be formed by means of insulating spacer plugs inserted between the prefabricated blocks.

[0125] In another embodiment of the embodiment shown in FIG. 12, the sealing device includes a plate 34, for example made of a plastic material such as PVC, which provides protection to the plastic film sheet 12 during pressure release, preventing it from coming into contact with the insulating pad 6 and being inserted into the spaces separating prefabricated blocks 4 and supporting structure 13.

[0126] Moreover, in this embodiment, the sealing device includes a protective steel angle 35, which is located along the auxiliary thermal barrier 1. Protective steel angle 35 includes a first flat flange that extends parallel to the supporting structure 13 and is attached to a rigid seal film 7, and a second flat flange, which extends in the direction of the thickness of the tank wall in the direction of the supporting structure 13 and is located on the side surfaces of the prefabricated blocks 4. The protective steel corner 35 is made, for example, of cardboard and protects the tarpaulin 12 made of polymer film from protruding corners auxiliary thermal insulating barrier 1.

[0127] The plate 34 preferably extends in the tank wall thickness direction toward the interior of the tank beyond the edge of the second flat flange of the protective angle steel 35 to prevent the resin film sheet 12 from coming into contact with the insulating liner 6.

[0128] In FIG. 4 illustrates a second embodiment of the first embodiment of the leak test apparatus. This second embodiment differs from the embodiment described with reference to FIG. 2 in that the leak test apparatus further includes an additional clamping device 25 for sealing the polymer film tarpaulin 12 to the supporting structure 13 and to the auxiliary sealing membrane 2.

[0129] This type of clamping device 25 includes pins 26 attached to a support structure 13. Support plates 27 are mounted on these pins 26 by any suitable means. For example, a pin 26 of this type includes a rod the end of which is threaded. The backing plate 27 has a hole passing through it and is mounted on a pin 26 such that the body of said pin extends through the hole which extends through the backing plate 27. A nut (not illustrated) is screwed onto the threaded end of the rod so as to press the backing plate 27 in the direction of the supporting structure 13. A support plate 27 of this type is, for example, a wooden strip and is positioned so as to abut the plastic film canvas 12 in line with the second strip of sealing compound 18 when the nut is screwed on.

[0130] The clamping device 25 further includes a support member including a base 28, a spacer 29, and a support plate 30. The base 28 is attached to the main thermal barrier 3. For example, the base 28 is attached to attachment points that are typically used to attach additional panels , used to complete the main thermal insulating barrier 3 during the construction of the tank. The spacer element 29 extends from the base 28 in the direction of the auxiliary sealing membrane 2. The edge of the spacer element 29, opposite the base 28, has a support plate 30, which is located in line with the first strip of sealing compound 17 and presses the plastic film tarpaulin 12 in line with a first strip of sealing compound 17. The pressure of said support plate 30 is adjustable by any suitable means; for example, the spacer 29 may be telescopic with a mobilizing system allowing for adjustment of the size of the spacer 29, or the spacer 29 may include threads engaging a nut which, when screwed, causes the support plate 30 to abut the plastic film canvas 12 etc.

[0131] At the corner level of a tank section whose auxiliary sealing membrane 2 is to be leak tested, for example at the corner level of a completed tank, the polymer film tarpaulin 12 may include folds to follow the geometry of the tank section at said corner level.

[0132] An alternative is to assemble multiple portions of the canvas 12 from a polymer film through a strip of adhesive sealing compound to provide additional sealing (not illustrated).

[0133] According to another alternative, the spacer sheet 33 illustrated in FIG. 1, Can be sealed to cover the corner. This cover 33 includes a first flat flange, a second flat flange and a third flat flange. The first flat flange extends in a plane parallel to the thickness direction of the reservoir and covers the extreme portion of the first side surface of the auxiliary thermal insulating barrier 1. The second flat flange extends in a plane parallel to the thickness direction of the reservoir and covers the extreme portion of the second side surface of the auxiliary thermal insulating barrier 1, the first the outermost portion and the second edge together form a projecting corner of the auxiliary thermal insulating barrier 1. The third flange extends in a plane perpendicular to the thickness direction of the reservoir and covers the auxiliary sealing membrane portion vertically in line with said outermost portions of the first and second side surfaces of the auxiliary thermal insulating barrier 1. This the cover 33 is made, for example, of stainless steel and is sealed with strips of adhesive sealing compound, as described above, applied between the third flange and the auxiliary sealing membrane 2 and between the first and second flanges and the supporting structure 13.

[0134] In this alternative embodiment, the polymer film tarpaulin 12 is capable of covering the spacer sheet 33 at a corner, or it can be sealed to said spacer sheet 33 by one or more strips of adhesive sealing compound similar to the first and/or second strip of adhesive. sealing compound.

[0135] According to another alternative, not illustrated, the cover sheet 33 is formed by molding it in place at the corners of the thermal barrier to provide a custom-made cover sheet 33. The cover sheet 33 is formed, for example, by molding a polyurethane adhesive . For this purpose, the corner area intended to receive the spacer sheet formed on site is covered in advance with an adhesive protective strip to prevent the polyurethane adhesive from coming into direct contact with the auxiliary sealing membrane 2 or the auxiliary thermal insulating barrier 1. The protective adhesive strip preferably consists of silicone and acrylic, as for the adhesive part, while the strip part (not the adhesive function, but the function of providing support for the adhesive and mechanical strength) is made of polyester with a thickness of 150 to 200 µm inclusive, preferably from 155 to 170 µm inclusive (Flashtape 5® from SOLVAY company). The fiberglass mat is then placed on the corner of the insulating barrier before being coated with polyurethane adhesive. According to one preferred embodiment, the polyurethane adhesive can be applied in two stages. After polymerization of the cover sheet 33, the adhesive tape is removed and the cover sheet 33 is secured with one or more additional strips of adhesive sealing compound similar to the first and/or second strips of adhesive sealing compound as in the previous embodiment.

[0136] Moreover, according to the embodiment illustrated in FIG. 13, the vacuum pump 31 is connected to the enclosed space through a connecting device such as that illustrated in FIG. 13. The connecting device includes a connecting steel angle 36, which is preferably manufactured by forming it in place in accordance with a process similar to that described above with reference to the spacer sheet 33. A connecting flange 37 for connection with the vacuum pump 31 , here it is embedded in the mass of the connecting steel angle 36 during its molding. After polymerization of the connecting steel angle 36, a hole is punched in the connecting steel angle 36 opposite the connecting flange 37 in order to relieve pressure in the enclosed space 19.

[0137] The connecting angle steel 36 is then secured in a similar manner to the cover sheet 33, in other words, by one or more additional strips of adhesive sealing compound similar to the first and/or second strips of adhesive sealing compound.

[0138] As shown in FIG. 13, the connecting angle steel 36 is preferably positioned to span two adjacent prefabricated blocks 4, such that the connecting flange 37 is located opposite the space formed between the two adjacent prefabricated blocks 4. This helps relieve pressure in the enclosed space 19.

[0139] Figures 5 to 11 illustrate various steps for installing a leak test apparatus according to the second embodiment. In these figures, identical elements or elements having the same function as the elements described above with reference to Figures 1-4 have the same reference number increased by 100. This second embodiment of the sealing device differs mainly in that the tarpaulin 12 of the polymer film is replaced by metal structures 112, as explained below.

[0140] FIG. 5 shows a plurality of adjacent prefabricated units 104, the rigid sealed films 107 of which are connected to each other by sections 111 of flexible sealed film. Similar to the first embodiment in the manner described above, the first step of installing the seal test apparatus according to the second embodiment consists of the step of applying a layer of polyurethane adhesive 121 to the outermost portions 116 of the flexible sealing film portions 111 configured to receive the first strip of sealing compound. 117, as illustrated in FIG. 6. These layers of polyurethane adhesive 121 provide good interaction between the first strip of sealing compound 117 and said end portions 116 of the flexible seal film portions 111.

[0141] During the second step of installing the sealing device, as illustrated in FIG. 7, a first strip of sealing compound 117 is sealed onto a peripheral portion 115 of the auxiliary seal membrane 2. Likewise, a second strip of sealing compound 118 is sealed onto the supporting structure 113 around the portion of the tank whose auxiliary sealing membrane 102 is to be leak tested.

[0142] During the third step, 133 is positioned at the level of the corner 134 formed by the auxiliary thermal barrier 101. This spacer sheet 33 is made, for example, of stainless steel.

[0143] The cover sheet 133 includes a first flat flange 135 and a second flat flange 136. The spacer sheet 133 is positioned at the level of the corner 134 such that the first flat flange 135 extends in a plane parallel to the thickness direction of the reservoir and covers the end portion 137 of the first side surface 138 of the auxiliary thermal insulating barrier 101. The cover sheet 133 is installed at the level of the corner 134 so that the second flat flange 136 extends in a plane parallel to the thickness direction of the reservoir and covers the outermost portion 139 of the second side surface 140 of the auxiliary thermal insulating barrier 101, with said first outermost the portion 137 and said second end portion 139 together form the corner 134 of the auxiliary thermal insulating barrier 101.

[0144] The cover sheet 133 further includes a third flat flange 141 and a fourth flat flange 142. The third flange 141 extends perpendicular to the first and second flat flanges 135, 136 from the inner edges of the first and second flat flanges 135, 136. Likewise, the fourth flat flange extends perpendicular to the first and second flat flanges 135, 136 from the outer edges of the first and second flat flanges 135, 136. As a result, the third flat flange 141 and the fourth flat flange 142 are parallel and extend in opposite directions from the opposite edges of the first and second flat flanges 135, 136. The cover sheet 133 is positioned at the level of the corner 134 such that the third flange 141 is sealed onto the first strip of sealant compound 117 and the fourth flange 142 is sealed onto the second strip of sealant compound 118. Thus, the cover sheet 133 is sealed through the strips of sealant compound 117 and 118 to the auxiliary sealing membrane 102 and to the supporting structure 113.

[0145] During the fourth step illustrated in FIG. 9, additional strips of adhesive sealing compound 143 are applied to edges of the cover sheet 133 that do not interact with the first strip of sealing compound 117 or the second strip of sealing compound 118.

[0146] During the fifth step illustrated in FIG. 10, a metal structure 144 is sealed between an auxiliary sealing membrane 102 and a support structure 113. A metal structure 144 of this type includes a flat center portion 145, a flat inner edge 146, and a flat outer edge 147. The inner edge 146 and the outer edge 147 extend perpendicular to the flat center portion 145. An inner edge 146 and an outer edge 147 extend from opposite edges of the flat center portion 145 and in opposite directions relative to said flat center portion 145. This metal structure 144 is positioned on the reservoir portion such that the inner edge 146 seals against the first strip of sealant. compound 117, and the outer edge 147 seals against the second strip of sealing compound 118, with the flat central portion 145 covering the side surface 138 of the thermal barrier. In addition, the metal structure 144 is positioned at the reservoir site such that one edge of the metal structure seals with one of the additional strips of sealing compound 143 located on the cover sheet 133. Typically, the inner edge 146 of the metal structure 144 seals with the additional strip of sealing compound 143 applied to the third flange 141 of the cover sheet 133, the flat central portion 145 of the metal structure 144 seals with the additional strip of sealing compound applied to the first flange 135 of the cover sheet 133, and the outer edge 147 of the metal structure 144 seals with the additional strip of sealing compound 143, applied to the fourth flange 142 of the cover sheet 133. In this regard, the metal structure 144 and the cover sheet 133 are sealed using an additional strip of sealing compound 143.

[0147] Cover sheets 133 and metal structures 144 of the above-mentioned type are similarly positioned around the entire periphery of the reservoir portion, the auxiliary sealing membrane 102 of which is to be leak-tested, in order to define an enclosed space 119, as illustrated in FIG. eleven.

[0148] This second embodiment of the leak test apparatus offers good reliability, wherein the cover sheets 133 and metal structures 144 are hard and there is no risk of damage. Moreover, the sealing of the enclosed space 119 is achieved simply and reliably thanks to the strips of sealing compound 117, 118 and 143. In addition, this leak test device is very easy to remove, since it is enough to simply remove the structures 144 and cover sheets 133 and then the strips of sealing compound 117 and 118 and it is possible to strip layers of polyurethane adhesive 121.

[0149] In order to ensure good interaction between, on the one hand, the structures 144 and the cover sheets 133 and, on the other hand, the first strip of sealing compound 117 and the second strip of sealing compound, force can be equally applied to the said structures 144 and the cover sheets 133 by means of a pressing device similar to that described above with reference to FIG. 4.

[0150] In addition, in order to eliminate inconsistencies associated with manufacturing tolerances of the reservoir section, the structures 144 and cover sheets 133 may be provided in two parts. The inner portion of the structure 144 in this case includes an inner edge 146 and the inner portion of the central portion 145, and the outer portion of the structure 144 includes the outer edge 147 and the outer portion of the central portion 145. The step of installing the structure 144 in this case includes the first step , on which the lower part or the upper part of the structure is installed, an additional strip of sealing compound is applied to the central portion of the said part and is installed enclosing the other part of the structure so that the lower part and the upper part of the central portion 145 are hermetically connected using an additional strip of sealing compound or by welding . By varying the overlap between the interior and exterior of the central portion 145, this embodiment of the embodiment allows for adaptation of the size of the central portion 145 to eliminate inconsistencies associated with tank manufacturing tolerances.

[0151] Similarly, flatness defects in the support structure 13, 113 can be eliminated by applying multiple layers of sealing compound to form a second strip of sealing compound 18, 118. Specifically, in the second embodiment of the airtightness test apparatus, flatness defects in the supporting structure 113 can create a discrepancy that may vary from 4 mm to 30 mm, with metal structures 144 or cover sheets 133. Application of multiple overlapping layers of sealing compound allows the formation of a second strip of sealing compound 118 with a thickness sufficient to fill these discrepancies associated with defects in the flatness of the supporting structure 113.

[0152] The description above is for the leak test of the auxiliary sealing membrane 2, 102, but the above-mentioned sealing devices can be installed in a similar manner for the leak test of the main seal membrane.

[0153] In the context of a main seal membrane leak test, the auxiliary seal membrane 2, 102 forms a flat and sealed bearing surface onto which a second strip of sealing compound 18, 118 is applied. In this embodiment, this flat and sealed bearing surface is formed by a leak testing device for leak testing of the auxiliary sealing membrane 2, 102. In another design, the second strip of sealing compound 18, 118 is applied to the supporting structure 13, 113, and the auxiliary sealing membrane 2, 102 is equally placed in the enclosed space 19, 119. The first strip of sealing compound 17, 117 are then applied to the main sealing membrane.

[0154] In addition, the clamping device 25 may in this case be adapted such that the base 28 includes a clamp, for example, of the spring latch type, capable of snapping onto the portion of the main sealing membrane that is to be tested for leaks. In the context of a main seal membrane including a first row of parallel corrugations and a second row of parallel corrugations forming nodes at the intersections between the corrugations of the first series of corrugations and the corrugations of the second series of corrugations, the base 28 may then snap onto the nodes of said main seal membrane.

[0155] Although the invention has been described with reference to many specific embodiments, it is clear that it is in no way limited to them and that it covers all technical equivalents of the described means and combinations thereof, if the latter are within the scope of protection of the invention, which is defined by the appended claims.

[0156] The use of the verb “include,” “comprise,” and their conjugate forms does not preclude the presence of elements or steps other than those set forth in the claim.

[0157] In the claims, any reference position within parentheses should not be interpreted as limiting the claim.

Claims (24)

1. A method for testing the tightness of a sealing membrane (2), wherein the sealing membrane (2) is attached to a heat-insulating barrier (1), and the heat-insulating barrier (1) lies on a sealed bearing surface (13), said method comprising the steps of: apply the first strip of sealing mastic (17) to the sealing membrane (2), apply a second strip of sealing mastic (18) to the bearing surface (13) around the sealing membrane (2), place the sealed coating (12) on the first strip of sealing mastic (17) and on the second strip of sealing mastic (18) so that on one side the sealed coating (12) is hermetically connected to the sealing membrane (2) using the first strip of sealing mastic (17 ), and on the other hand, the sealed coating (12) is hermetically connected to the bearing surface (13) using the second strip of sealing mastic (18), while the sealed coating (12), the bearing surface (13), the first strip of sealing mastic (17) , the second strip of sealing mastic (18) and the sealing membrane (2) together form an enclosed space (19), where the sealing cover includes a tarpaulin of polymer film; releasing the pressure in the enclosed space (19) relative to the environment outside said enclosed space (19) and measuring a parameter representing the change in pressure inside the enclosed space (19) after the pressure in said enclosed space (19) is released. 2. The leak test method according to claim 1, wherein the sealing membrane (2) includes at least one portion (11) of a composite seal film, said method further comprising the step of applying an adhesive layer (21) to surface of said at least one section (11) of the composite sealing film such that said adhesive layer (21) is absorbed into the section (11) of the composite film, wherein a first strip of sealing mastic (17) is applied to said surface of the said at least one section (11) of the composite film. 3. The leak testing method according to claim 2, wherein the adhesive layer (21) is a polyurethane adhesive layer. 4. The method of testing for leaks according to any one of paragraphs. 1-3, in which the first strip of sealant (17) is adhesive and the second strip of sealant (18) is adhesive. 5. The method of testing for leaks according to any one of paragraphs. 1-4, in which the first strip of sealant (17) is made of synthetic rubber and the second strip of sealant (18) is made of synthetic rubber. 6. Method of testing for leaks according to any one of paragraphs. 1-5, wherein the polymer film tarpaulin is made from a material selected from vinyl, nylon and polyethylene. 7. Method of testing for leaks according to any one of paragraphs. 1-6, further including the step of placing a screen (22, 34) covering the gap between the thermal insulating barrier (1) and the load-bearing surface (13) to prevent the polymer film canvas from being positioned in said gap during dumping pressure in a confined space (19). 8. The method of testing for leaks according to any one of paragraphs. 1-7, further including the step of positioning a protective steel angle (35) including a first flat flange and a second flat flange such that the first flat flange is positioned on the sealing membrane (2) and the second flat flange is extended along the edge of the heat-insulating barrier (1) and protrudes towards the load-bearing surface (13). 9. Method of testing for leaks according to any one of paragraphs. 1-8, in which a reinforcing fabric (23) is attached to a tarpaulin made of a polymer film, and the tarpaulin is attached in such a way that the reinforcing fabric (23) is located in a closed space (19) at the level of the corner formed by the heat-insulating barrier (1). 10. Method of testing for leaks according to any one of paragraphs. 1-9, further including the step of applying a support reaction force in the direction of the load-bearing surface (13) to the sealing cover (12) in line with the first strip of sealant mastic (17) and in line with the second strip of sealant mastic ( 18). 11. Method of testing for leaks according to any one of paragraphs. 1-10, further including the step of securing a cover sheet (33) at the level of a corner of the thermal barrier (1) such that said cover sheet (33) covers said corner, wherein the cover sheet (33) is sealed at one side with a bearing surface (13), and on the other side with a sealing membrane (2). 12. The leak testing method according to claim 11, wherein the cover sheet (33) is manufactured by in-situ molding of a heat insulating barrier (1) at a corner. 13. Method of testing for leaks according to any one of paragraphs. 1-12, including the step of positioning a connecting device including a connecting angle steel (36) and a connecting flange (37) positioned opposite an opening formed in said connecting angle steel (36), wherein said connecting angle steel (36) is tightly connected to the bearing surface (13), to the sealing membrane (2) and to the sealing cover (12), and the connecting flange (37) is tightly connected to the pressure relief means (31) in the enclosed space (19). 14. The leak test method according to claim 13, wherein the connecting steel angle (36) is manufactured by molding it in place on the thermal insulating barrier (1), and the connecting flange (37) is embedded into the mass of the connecting steel angle (36) during its molding. 15. A sealing device for closing an enclosed space (19) formed between a sealing membrane (2) attached to a thermal insulating barrier (1) attached to a bearing surface (13) and said bearing surface (13); wherein the sealing device includes sealed covering (12), hermetically connected on one side to the sealing membrane (2) by means of the first strip of sealing mastic (17), and on the other hand to the bearing surface (13) by means of the second strip of sealing mastic (18), where the sealing covering (12 ) includes a tarpaulin made of polymer film; And a vacuum pump connected to the enclosed space (19) and capable of relieving pressure in said enclosed space (19). 16. The sealing device according to claim 15, wherein the sealing device further includes a screen (22) covering the gap between the thermal insulating barrier (1) and the load-bearing surface (13) so as to bridge said gap and prevent insertion of the polymer film tarpaulin during the mentioned period under pressure release conditions in a confined space (19). 17. The sealing device according to claim 15 or 16, additionally including a clamping device (25) configured to apply a support reaction force in the direction of the bearing surface (13) to the sealing coating (12) in line with the first and second sealing strips mastics (17, 18).