Fusible sealing device

Abstract

A sealing device for sealing a joint formed by two adjacent assembly elements (2), comprising: a filler layer (11) intended to be positioned in a gap (7) formed by the joint between the two assembly elements (2); a sealing coating (12) disposed above the filler layer (11) and intended to extend at least partially onto the surface of the assembly elements (2) on either side of the gap (7), the sealing coating comprising a lamination layer (13) comprising at least one thermosetting or thermoplastic material containing glass fibers of length less than or equal to 150 mm, the sealing coating having a maximum elongation at break εmax, expressed in %; the filler layer (11) having an elongation at break less than or equal to the elongation at break of the sealing coating (12). Figure for the abbreviation: Fig 1

Description

Title of the invention: Fusible sealing device

[0001] The present application relates to a sealing device for sealing a joint formed by the assembly of two adjacent assembly elements allowing relative movement to be obtained between the two assembly elements when a force is applied, for example in an accidental situation.

[0002] In particular, the invention relates to a digester dome comprising such a sealing device for the purpose of obtaining a level difference when accidental overpressure occurs within the digester.

[0003] A biogas digester or reactor refers to a structure that allows methane to be formed from various organic materials which can then be used as an energy source.

[0004] Generally, the concrete structure comprises a large cylindrical tank for containing decomposing organic sludge, topped with a dome closing the tank.

[0005] During operation, some digesters operate at temperatures ranging from 35°C to 55°C and at an overpressure of up to 40 mbar. The atmosphere inside the structure is explosive and there remains a risk of a significant increase in pressure, leading to a "pressure cooker" effect and ultimately an explosion and sudden rupture of the concrete, accompanied by the projection of concrete blocks in the surrounding area.

[0006] In order to avoid such an accident scenario, there are valve systems. However, there have been cases where these systems do not work properly.

[0007] Furthermore, given the aggressiveness of the gaseous atmosphere present within the structure and in order to protect the concrete, it is advisable to apply an anti-corrosion coating to the inner face of the dome and the tank in vertical fall in a veil down to below the level of the sludge.

[0008] Furthermore, the rules of the art concerning the construction of concrete tanks require, for protection against gaseous clouds, that the anti-corrosion coating be a sealing coating and not a waterproofing coating.

[0009] The present invention therefore aims to overcome the aforementioned drawbacks by proposing a structure, such as a digester, provided with a sealing treatment and allowing effective degassing during an overpressure event in order to avoid any risk of explosion.

[0010] According to one aspect of the invention, there is therefore proposed a sealing device intended to seal a joint formed by two adjacent assembly elements, comprising:

[0011] a filling layer intended to be positioned in a gap formed by the joint between the two assembly elements; and

[0012] a sealing coating arranged above the filling layer and intended to further extend at least partially on the surface of the assembly elements on either side of the gap, the sealing coating comprising at least one thermosetting or thermoplastic material comprising glass fibers of a length less than or equal to 150 mm, the sealing coating having a maximum elongation at break emax expressed in %, with:

[0013] &max —

[0014] where Dmax, expressed in mm, is a maximum relative movement allowed before rupture between the two adjacent assembly elements, l0, expressed in mm, is a width of the joint between the two adjacent assembly elements, and cos y, without unit, is the cosine of the angle formed between the direction of the relative movement between the two adjacent assembly elements and the direction of the width of the joint between the two adjacent assembly elements;

[0015] the filling layer having an elongation at break less than or equal to the elongation at break of the sealing coating.

[0016] When the relative movement moves the two adjacent assembly elements apart, the angle y is > 90°. When the relative movement brings the two adjacent assembly elements together, the angle y is < 90°. When the relative movement is perpendicular to the width of the joint, the angle y is = 90°.

[0017] In one embodiment, the elongation at break of the filler layer and the elongation at break of the sealant coating may be considered at room temperature, for example 23°C.

[0018] The elongation at break is measured according to standards NF EN ISO 527-4, NF EN ISO 527-2 and NF ISO 527-1.

[0019] The elongation at break of resins incorporating a glass reinforcement is measured using standard NF EN ISO 527-4. The elongation at break of resins alone, without reinforcement, is measured using standard NF EN ISO 527-2. Standard NF EN ISO 527-1 gives the general principles and complements standards NF EN ISO 527-2 and NF EN ISO 527-4.

[0020] In one embodiment, the sealing coating may have an elongation at break of less than or equal to 3%.

[0021] In one embodiment, the filler layer may have an elongation at break of between 0.1 and 0.75%.

[0022] In one embodiment, the sealing coating may have an elongation at break of less than or equal to 3% and the filler layer may have an elongation at break of between 0.1 and 0.75%.

[0023] According to one embodiment, the filling layer may comprise a coating comprising at least one thermosetting or thermoplastic material and having a viscosity greater than or equal to 250,000 mPa.s at 20°C. The filling layer may then be applied to the inner face of the dome 1 in a thick layer without it falling or flowing downwards.

[0024] Preferably, the thermosetting or thermoplastic material of the coating has a viscosity ranging from 250,000 to 700,000 mPa.s at 20°C. The viscosity is measured using a rotational viscometer. The device used is a Brookfield RVDV-I PRIME viscometer. The standards used are NF EN ISO 3219 and NF EN ISO 2555.

[0025] The thermosetting or thermoplastic material of the coating may comprise at least one rheological agent.

[0026] Preferably, the thermosetting or thermoplastic material of the coating comprises at least one rheological agent chosen from: mineral fillers such as silica, synthetic fillers such as polyethylene fibers, organic fillers such as wood flour, metallic fillers, organic additives, or a mixture thereof.

[0027] According to one embodiment, the thermosetting or thermoplastic material of the coating comprises an epoxy resin.

[0028] According to one example, the coating may comprise an epoxy resin incorporating silica.

[0029] Preferably, the thickness of the coating of the filling layer is between 5 and 20 mm, preferably between 10 and 15 mm.

[0030] Preferably, the glass fibers of the laminating layer are present in the form of a glass mat, preferably a glass mat having a grammage of 300 g / m2.

[0031] Advantageously, the laminating layer may comprise a first sub-layer of epoxy resin arranged above the filling layer, a glass mat arranged on the first sub-layer and a second sub-layer of epoxy resin arranged above the glass mat.

[0032] Advantageously, the sealing coating may comprise a finishing layer arranged above the lamination layer.

[0033] Preferably, the finishing layer has chemical resistance properties suitable for the effluents present in the environment of the sealing device, or present in a structure comprising the sealing device. For example, the finishing layer has anti-corrosion properties.

[0034] According to one embodiment, the finishing layer may comprise at least one thermosetting or thermoplastic material.

[0035] According to one embodiment, the finishing layer may comprise at least one thermosetting or thermoplastic material incorporating at least one rheological agent.

[0036] Preferably, the thermosetting or thermoplastic material of the finishing layer incorporates fillers and / or at least one rheological agent chosen from: mineral fillers such as silica, synthetic fillers such as polyethylene fibers, organic fillers such as wood flour, metallic fillers, organic additives, or a mixture thereof.

[0037] Preferably, the sealing device comprises a support layer, for example a joint backing, intended to be positioned in the gap below the filling layer. The layer is, for example, made of polyurethane foam.

[0038] According to one embodiment, the sealing coating has, at a temperature of 55°C, a maximum elongation at break emax expressed in %, with:

[0039] = -----------'i-----------X 100 'o

[0040] where Dmax, expressed in mm, is a maximum relative movement allowed before rupture between the two adjacent assembly elements, l0, expressed in mm, is a width of the joint between the two adjacent assembly elements, and cos y , without unit, is the cosine of the angle formed between the direction of the relative movement between the two adjacent assembly elements and the direction of the width of the joint between the two adjacent assembly elements.

[0041] In one embodiment, the sealing coating may have, at a temperature of 55°C, an elongation at break of less than or equal to 3%.

[0042] In one embodiment, the filling layer may have, at a temperature of 55°C, an elongation at break of between 0.1 and 0.75%.

[0043] In one embodiment, at a temperature of 55°C, the sealing coating may have an elongation at break of less than or equal to 3% and the filling layer may have an elongation at break of between 0.1 and 0.75%.

[0044] The invention also relates to a system comprising at least two adjacent assembly elements forming a seal and a sealing device for said seal as described above.

[0045] According to one characteristic, the gap may comprise beveled edges forming a groove opening onto the surface of the assembly elements.

[0046] In one embodiment, the assembly elements may be made of concrete.

[0047] Advantageously, the system may comprise a plurality of assembly elements distributed into first sets of assembly elements and second sets of assembly elements comprising a smaller number of assembly elements than said first sets, said first and second sets being arranged alternately.

[0048] The invention also relates to a dome intended to close a digester tank, comprising a plurality of adjacent assembly elements each formed by a petal extending radially between the center of the dome and the periphery of the dome, and comprising an even number of sealing devices as described above, each sealing two adjacent assembly elements of the plurality of assembly elements to obtain relative movement between the adjacent assembly elements forming a seal sealed by said sealing device in the event of accidental overpressure within the digester.

[0049] Advantageously, each assembly element may comprise an outer face and an opposite inner face, all of the inner faces of the assembly elements forming an inner face of the dome intended to be positioned opposite the interior of the digester, the inner face of the dome being coated with a sealing coating arranged in continuity with the sealing coating of the sealing device.

[0050] The invention also relates to a method for obtaining a sealing device as described above, comprising a step of forming the filling layer and a step of forming the sealing coating, the step of forming the filling layer and / or the step of forming the sealing coating being carried out at least in part by spraying from a spraying machine.

[0051] Other characteristics, aspects and advantages of the invention will appear more clearly on reading the detailed description of four embodiments of the invention, which are in no way limiting, and the appended drawings in which:

[0052] [Fig. 1] represents a digester dome formed by a plurality of petals according to an embodiment in accordance with the invention;

[0053] [Fig.2] represents a petal of the dome illustrated in [Fig.l];

[0054] [Fig.3] represents an assembly of two petals as illustrated in [Fig.2], comprising a sealing device according to one embodiment of the invention;

[0055] [Fig.4] illustrates a sealing device according to one embodiment of the invention.

[0056] [Fig.5A] and [Fig.5B] illustrate the relative movement between two adjacent assembly elements moving apart.

[0057] [Fig.6A] and [Fig.6B] illustrate the relative movement between two adjacent assembly elements approaching each other.

[0058] In what follows, the limits of a domain of values ​​are included in this domain, in particular in the expressions “between” and “ranging from... to...”.

[0059] Furthermore, the expression “at least one” used in the present description is equivalent to the expression “one or more”.

[0060] The example developed below relates to a biogas digester or reactor intended to the formation of methane from decomposing organic sludge. The digester comprises a cylindrical tank closed by a dome 1 illustrated in [Fig.l].

[0061] The illustrated dome 1 comprises a plurality of concrete assembly elements 2.

[0062] Advantageously, the dome 1 comprises first sets 3 of assembly elements and second sets 4 of assembly elements comprising a smaller number of assembly elements 2 than the first sets 3. The first and second sets 3, 4 are arranged alternately.

[0063] In the example illustrated, each assembly element 2 is formed by a petal, illustrated in [Fig.2], which extends radially from the center of the dome to the periphery of the dome.

[0064] The general shape of the petals is a spherical isosceles triangle.

[0065] The dome 1 forms a corolla comprising a total of fifty-six petals. Four first sets 3 each comprise twelve petals and four second sets 4 each comprise two petals.

[0066] Preferably, the adjacent assembly elements 2 are connected two by two by steel reinforcements, with the exception of the junctions between two assembly elements 2, one of which belongs to one of the first sets 3 and the other belongs to one of the second sets 2. The first and second sets 3, 4 of assembly elements are not connected to each other.

[0067] In the illustrated example, eight junctions 5 between an assembly element 2 of first set 3 and an assembly element 2 of second set 4 are not connected and thus form a dry joint.

[0068] Furthermore, the dome 1 comprises a plurality of sealing devices 6 intended to seal a joint formed between an assembly element 2 of first sets 3 and an assembly element 2 of second adjacent sets 4.

[0069] Advantageously, the dome 1 comprises an even number of sealing devices 6.

[0070] In the example illustrated, the dome 1 comprises eight sealing devices 5 each positioned in one of the eight junctions 5 between an assembly element 2 of the first set 3 and an assembly element 2 of the second set 4.

[0071] [Fig. 3] illustrates a junction 5 between an assembly element 2 of first set 3 and an assembly element 2 of second set 4.

[0072] In this embodiment, the two adjacent assembly elements 2 are separated by a gap 7.

[0073] In the example illustrated, the two adjacent assembly elements 2 each comprise a first face 2a forming the current part of the structure. The first faces 2a are arranged on either side of the gap 7 on the surface of the assembly elements 2.

[0074] In the example illustrated, the first faces 2a are interior faces positioned facing the interior of the digester.

[0075] Fourth faces 2d, opposite the first faces 2a, are positioned towards the outside of the digester.

[0076] In addition, the two adjacent assembly elements 2 each comprise a second face 2b arranged opposite the gap 7. The second faces 2b are positioned opposite each other.

[0077] Beveled edges 2c are also provided in the interval 7 so as to form a groove opening on the one hand onto the first faces 2a and on the other hand onto the second faces 2b.

[0078] The presence of beveled edges 2c makes it possible to improve the mechanical resistance of the concrete.

[0079] In the example illustrated, the two adjacent assembly elements 2 each comprise a shoulder 8 opening on the one hand onto the second faces 2b and on the other hand onto the fourth faces 2d.

[0080] The cohesion between the two adjacent assembly elements 2 is created by two additional adjacent concrete blocks 9a and 9b arranged in the shoulders 8 and held against each other by compression. Their junction 10 extends in a plane passing through the gap 7.

[0081] The junction 10 between the concrete blocks 9a and 9b is formed by a dry joint, i.e. not bonded.

[0082] With reference to [Fig.4], the sealing device 6 intended to seal the joint formed between the two adjacent assembly elements 2 is a fusible sealing device.

[0083] By fusible sealing device is meant a sealing device capable of breaking upon application of a force which, in the illustrated example, is associated with an accidental overpressure situation, and which, by breaking, allows the formation of a relative movement between two adjacent assembly elements 2.

[0084] By relative movement is meant a movement of one of the assembly elements 2 relative to the other of the two adjacent assembly elements 2, leading to an offset between the two adjacent assembly elements 2.

[0085] In the example illustrated, the relative movement results in a misalignment, obtained by the lifting of the petals of the dome 1.

[0086] The sealing device 6 comprises a filling layer 11 positioned in the gap 7.

[0087] Preferably, the filling layer 11 extends to the surface of the gap 7 so as to form continuity with the first faces 2a of the adjacent assembly elements 2, that is to say up to the horizontal plane passing through the first faces 2a of the adjacent assembly elements 2.

[0088] Preferably, a support layer 15 joint backing 15 is positioned in the gap 7 below the filling layer 11.

[0089] In the illustrated example, the support layer is a joint backing and is a polyurethane foam. The polyurethane foam can be leveled to the desired height, in order to precisely control the thickness of the coating of the filling layer 11 applied to its surface.

[0090] The support layer 15 advantageously makes it possible to more easily control the thickness of the filling layer 11 in the interval 7.

[0091] A sealing coating 12 extends above the filling layer 11 and on either side of the gap 7, on the surface of the assembly elements 2.

[0092] Preferably, the sealing coating 12 is positioned directly on the filling layer 11.

[0093] The sealing coating 12 has a maximum elongation at break emax, expressed in %, with:

[0094] x]DmalhlQ-2xD„^^ ----------1----------- X 100

[0095] where Dmax, expressed in mm, is the maximum relative movement allowed before rupture between the two adjacent assembly elements 2. l0, expressed in mm, is the width of the joint between the two adjacent assembly elements. In addition, cos y, without unit, is the cosine of the angle y formed between the direction of the relative movement between the two adjacent assembly elements and the direction of the width of the joint between the two adjacent assembly elements 2.

[0096] In the example illustrated, the angle y formed between the direction of relative movement between the two adjacent assembly elements and the direction of the width of the joint between the two adjacent assembly elements 2 is equal to the angle formed between the direction of relative movement between the two adjacent assembly elements and the plane passing through the sealing coating 12.

[0097] Figures 5A and 6A illustrate a relative movement between the two adjacent assembly elements 2.

[0098] As illustrated in [Fig.5A], when one of the two adjacent elements 2, referenced B, is moving relative to the other, referenced A and fixed, the relative movement can move the two adjacent assembly elements 2 apart, and the angle y represented in [Fig.5B] is then greater than 90°.

[0099] As illustrated in [Fig. 6A], when one of the two adjacent elements 2, referenced B, is moving relative to the other, referenced A and fixed, the relative movement can bring the two adjacent assembly elements 2 closer together, and the angle y represented in [Fig. 6B] is then less than 90°.

[0100] When the relative movement is perpendicular to the width of the joint l0, the angle y is equal to 90°.

[0101] In the example illustrated, the relative movement results in a misalignment, obtained by the lifting of the petals of the dome 1 according to which, when one of the two adjacent elements 2 is in movement relative to the other, the relative movement is substantially perpendicular to the width of the joint, with an angle y substantially equal to 90°.

[0102] The filling layer 11 has an elongation at break less than or equal to the elongation at break of the sealing coating 12.

[0103] Advantageously, the sealing coating 12 may have an elongation at break of less than or equal to 3%.

[0104] Advantageously, the filling layer 11 may advantageously have an elongation at break of between 0.1 and 0.75%.

[0105] Elongation at break defines the ability of a material to elongate before breaking when subjected to tensile stress.

[0106] In the present invention, the elongation or deformation at break is measured by tensile tests according to standard NF EN ISO 527-4.

[0107] In the example illustrated, the filling layer 11 comprises a coating comprising at least one thermosetting or thermoplastic material.

[0108] Preferably, the coating has a viscosity greater than or equal to 250,000 mPa.s. From 250,000 mPa.s the coating is advantageously sufficiently viscous to be applied to a surface. The coating can thus be applied to the inner face of the dome 1 in a thick layer without it falling or flowing downwards.

[0109] Preferably, the thermosetting or thermoplastic material of the coating has a viscosity ranging from 250,000 to 700,000 mPa.s at 20°C. Above 700,000 mPa.s it is very viscous so that the coating is difficult to apply.

[0110] Viscosity means the dynamic viscosity of the thermosetting or thermoplastic material measured at 20°C using a rotational viscometer.

[0111] According to one example, the thermosetting or thermoplastic material of the coating may be an epoxy resin. The thermosetting or thermoplastic material, such as epoxy resin, may incorporate at least one rheological agent.

[0112] Preferably, the thermosetting or thermoplastic material of the coating comprises at least one rheological agent chosen from: mineral fillers such as silica, synthetic fillers such as polyethylene fibers, organic fillers such as wood flour, metallic fillers, organic additives, or a mixture thereof.

[0113] In the example illustrated, the coating comprises an epoxy resin incorporating silica and has an elongation at break of 0.56%.

[0114] By coating is meant a material comprising a binder or glue and at least one filler.

[0115] It may be provided that the thermosetting or thermoplastic material incorporates mineral fillers other than silica, other rheological agents or their mixtures.

[0116] According to one example, the thermosetting or thermoplastic material of the coating may be chosen from bisphenol A diglycidyl ether (DGEBA), bisphenol F diglycidyl ether (DGEBF) and mixtures thereof.

[0117] In the example illustrated, the sealing coating 12 comprises a first layer, hereinafter called the lamination layer 13, comprising at least one thermosetting or thermoplastic material comprising short glass fibers, of length less than or equal to 150 mm.

[0118] According to an exemplary embodiment, the lamination layer 13 may comprise at least one epoxy resin.

[0119] Advantageously, the laminating layer 13 made of thermosetting or thermoplastic material comprising glass fibers may comprise a first sub-layer of epoxy resin arranged above the filling layer 11, a glass mat arranged on the first sub-layer and a second sub-layer of epoxy resin arranged above the glass mat.

[0120] The first epoxy resin undercoat and the second epoxy resin undercoat respectively impregnate and then saturate the fibers of the glass mat.

[0121] By glass mat is meant a fabric formed by the agglomeration of short glass fibers without weaving or particular orientation bound together by a binder which, in the example illustrated, is an epoxy resin.

[0122] Preferably, the length of the glass fibers of the glass mat is between 20 and 40 mm.

[0123] The discontinuity of the short glass fibers of 150 mm maximum makes it possible to form a fragile material, and to obtain a fairly rapid rupture after a small deformation, unlike the long fibers which tend to align during a tensile stress forming a more ductile material.

[0124] Preferably, the glass fibers of the laminating layer 13 are present in the form of a glass mat, preferably a glass mat having a grammage of 300 g / m2. Such a thickness makes the glass mat both sufficiently deformable and brittle.

[0125] Preferably, the sealing coating 12 comprises a second layer, hereinafter referred to as the finishing layer 14, arranged above the laminating layer 13.

[0126] Preferably, the finishing layer 14 has physicochemical properties that allow it to remain in contact with the potentially aggressive and corrosive contents of the digester tank such as sludge, chemicals, etc.

[0127] In this regard, the finishing layer 14 advantageously has chemical resistance properties adapted to the effluents present in the digester, for example anti-corrosion properties.

[0128] In an exemplary embodiment, the finishing layer 14 may comprise at least one thermosetting or thermoplastic material incorporating fillers having chemical resistance properties adapted to the effluents present in the digester.

[0129] In this regard, according to one embodiment, the finishing layer 14 may comprise at least one thermosetting or thermoplastic material incorporating fillers.

[0130] Certain fillers incorporated into the thermosetting or thermoplastic material can form a rheological agent by exhibiting properties making it possible to control the viscosity of the thermosetting or thermoplastic material.

[0131] Preferably, the thermosetting or thermoplastic material of the finishing layer 14 incorporates fillers and / or at least one rheological agent chosen from: mineral fillers such as silica, synthetic fillers such as polyethylene fibers, organic fillers such as wood flour, metallic fillers, organic additives, or a mixture thereof.

[0132] According to an exemplary embodiment, the finishing layer 14 comprises an epoxy resin incorporating silica.

[0133] The presence of fillers, such as silica, in the thermosetting or thermoplastic material of the finishing layer 14 also makes it possible to improve adhesion to the laminating layer 13.

[0134] The presence of rheological agent makes it possible to apply the finishing layer 14 to the inner face of the dome 1 without dripping.

[0135] In the example illustrated, the inner face of the dome 1 is coated, on the running part, that is to say on the first faces of each assembly element 2 forming the dome, on either side of the sealing coating 12 of the sealing device 6, with a sealing coating 16.

[0136] According to one example, the sealing coating 16 of the running part may comprise a laminating layer 17 and a finishing layer 18.

[0137] The laminating layer 17 may comprise a thermosetting or thermoplastic material, for example an epoxy resin, incorporating a reinforcement, for example a fabric, of multi-axial glass or bi-diagonal non-woven glass reinforcement.

[0138] The finishing layer 18 may comprise a thermosetting or thermoplastic material having anti-corrosion properties intended to protect the assembly elements 2 from the corrosive atmosphere inside the digester.

[0139] In the illustrated example, the sealing device 6 comprises a sealing coating 12 having a maximum elongation at break emax and a filling layer 11 having an elongation at break less than or equal to that of the sealing coating. The filling layer 11 and the sealing coating 12 of such a sealing device 6 are fragile and therefore brittle.

[0140] Thus, the sealing device 6 which is brittle and not very deformable is capable of breaking quickly by a clean break in the width of the seal under the action of a sufficient force or stress which, in the example illustrated, corresponds to an accidental overpressure occurring within the digester.

[0141] Advantageously, the filling layer 11 may have an elongation at break lower than that of the sealing coating 12 so that the filling layer 11 initiates the rupture of the sealing device 6.

[0142] Furthermore, given the presence of short glass fibers in the sealing coating 12, their rupture initiates and facilitates the rapid rupture of the sealing coating 12.

[0143] Advantageously, the sealing device 6 breaks between 0 and 8 mm of displacement of the assembly elements 2.

[0144] In the illustrated example, the digester operates at 55°C and the sealing device 6 comprises a filling layer 11 and a sealing coating 12 having, respectively, an elongation at break of less than or equal to 3% and between 0.1 and 0.75%, at a temperature of 55°C.

[0145] Advantageously, the thickness of the coating of the filling layer 11 is between 5 and 20 mm, preferably greater than 5 mm and less than 20 mm, and more preferably still between 10 and 15 mm.

[0146] For a coating thickness of less than 5 mm, the filling layer 11 is not sufficiently brittle and there is a risk of breakage by peeling.

[0147] By peeling is meant the detachment of the sealing device 6.

[0148] When the filling layer 11 is not brittle enough, and its capacity to de formation before rupture is therefore too great. There is no rupture and the layer detaches. When the sealing device 6 is too ductile, it detaches without breaking, and degassing of the digester cannot occur or occurs too late to avoid an explosion.

[0149] Beyond a thickness of 20 mm, the assembly elements 2 risk being too strongly linked, so that accidental overpressure within the digester is not sufficient to cause the sealing device 6 to rupture.

[0150] In the example illustrated, the glass transition temperature Tg of the epoxy resins of the sealing device 6 is advantageously greater than 40°C so as to be slightly deformable and sufficiently brittle at 55°C.

[0151] The glass transition temperature Tg corresponds to the temperature at which a material passes from a brittle, fragile state to a more ductile state. The transition is gradual as the temperature increases, ductility begins to appear before the Tg, and increases further after exceeding the Tg.

[0152] In the event of accidental overpressure within the digester, the pressure rises within the digester and the petals begin to lift. The second sets 4 of petals, which are lighter, lift more than the first sets 3.

[0153] The fusible sealing device 6 is brittle and breaks cleanly thanks to the lifting of the second sets 4 of petals.

[0154] The clean break of the filling layer 11 causes the sealing coating 12 to fail. The fragile and non-ductile nature of the filling layer 11 and the sealing coating 12 promotes a clean break without too much deformation before breaking the sealing device 6.

[0155] The joints sealed under normal operating conditions of the structure are thus released and a gap is created between the first and second sets of assembly elements. This gap will open the gaseous air of the digester to the open air and allow degassing in order to avoid an explosion of the digester.

[0156] Such a sealing device 6 is easily repairable after the occurrence of overpressure and degassing by flushing the assembly elements that it seals. The sealing device 6 can be replaced and the digester quickly put back into service.

[0157] In the example illustrated, the seal formed by the assembly of the adjacent sealed assembly elements 2 relates to the digester dome 1.

[0158] Of course, the present invention applies to any other system comprising adjacent assembly elements forming a joint requiring sealing and having to break under a determined force such as accidental overpressure or any other force.

[0159] Tensile tests were carried out at 55°C on a sealing device 6 applied to a joint formed between two adjacent assembly elements 2 and having the following dimensions: length of 400 mm, width of 200 mm, height of 60 mm and beveled or chamfered edges of 20 mm, and spaced by an interval 7 of width 10 mm.

[0160] The sealing device 6 on which the tensile tests were carried out comprises a filling layer 11 comprising an epoxy resin coating incorporating silica. The filling layer 11 has an elongation at break of 0.56% at 55°C.

[0161] The sealing coating 12 comprises a laminating layer 13 comprising a first epoxy resin underlayer, a glass mat with a weight of 300 g / m2, and a second undercoat of epoxy resin.

[0162] A topcoat 14 comprises an epoxy resin comprising silica.

[0163] The sealant coating 12 has an elongation at break of 2% at 55°C.

[0164] The epoxy resin of the coating of the filler layer 11 has a glass transition temperature Tg of 52.7°C.

[0165] The epoxy resin incorporating the glass mat comprising short fibers less than or equal to 150 mm of the lamination layer 13 of the sealing coating 12 has a glass transition temperature Tg of 43.2°C.

[0166] The glass transition temperatures Tg are measured according to the NF EN ISO 11357-2 standard.

[0167] The epoxy resin of the coating of the filling layer 11 and the epoxy resin of the sealing coating 12 are slightly deformable and brittle at 55°C.

[0168] In the example illustrated, the normal operating pressure of the digester is 40 mbar and the explosion of the digester occurs at a pressure of approximately 170 mbar.

[0169] For a thickness of the coating of the filling layer 11 of between 10 and 15 mm, the sealing device 6 studied is sufficiently brittle and not very deformable and is capable of breaking by a clean break in the width of the joint from 80 mbar and before 100 mbar, i.e. before reaching a displacement of 8 mm between the two assembly elements 2, in order to avoid an explosion of the digester.

Claims

Claims

1. A sealing device for sealing a joint formed by two adjacent assembly elements (2), comprising: a filling layer (11) intended to be positioned in a gap (7) formed by the joint between the two assembly elements (2); and a sealing coating (12) arranged above the filling layer (11) and intended to further extend at least partially on the surface of the assembly elements (2) on either side of the gap (7), the sealing coating comprising a lamination layer (13) comprising at least one thermosetting or thermoplastic material comprising glass fibers of a length less than or equal to 150 mm, the sealing coating has a maximum elongation at break emax, expressed in %, with: = / x 100 '0 where Dmax, expressed in mm, is a maximum relative movement allowed before breakage between the two adjacent assembly elements (2), l0, expressed in mm,is a width of the joint between the two adjacent assembly elements (2), and cos y, without unit, is the cosine of the angle formed between the direction of the relative movement between the two adjacent assembly elements (2) and the direction of the width of the joint between the two adjacent assembly elements (2); the filling layer (11) having an elongation at break less than or equal to the elongation at break of the sealing coating (12).,

2. Device according to claim 1, in which the sealing coating has an elongation at break of less than or equal to 3%.

3. Device according to claim 1 or 2, wherein the filling layer (11) has an elongation at break of between 0.1 and 0.75%.

4. Device according to any one of the preceding claims, in which the filling layer (11) comprises a coating comprising at least one thermosetting or thermoplastic material and having a viscosity greater than or equal to 250,000 mPa.s at 20°C, preferably having a viscosity ranging from 250,000 to 700,000 mPa.s at 20°C.

5. Device according to any one of the preceding claims, in wherein the thickness of the coating of the filling layer (11) is between 5 and 20 mm, preferably between 10 and 15 mm.

6. A device according to any preceding claim, wherein the glass fibers of the laminating layer (13) are present in the form of a glass mat, preferably a glass mat having a grammage of 300 g / m2.

7. A device according to any preceding claim, wherein the laminating layer (13) comprises a first epoxy resin sub-layer disposed above the filler layer (11), a glass mat disposed on the first sub-layer and a second epoxy resin sub-layer disposed above the glass mat.

8. A device according to any preceding claim, wherein the sealing coating (12) comprises a finishing layer (14) disposed above the laminating layer (13), preferably a finishing layer (14) having chemical resistance properties suitable for effluents present in the environment of the sealing device, or present in a structure comprising the sealing device.

9. Device according to claim 8, in which the finishing layer (14) comprises a thermosetting or thermoplastic material incorporating fillers and / or at least one rheological agent, preferably chosen from: mineral fillers such as silica, synthetic fillers such as polyethylene fibers, organic fillers such as wood flour, metallic fillers, organic additives, or a mixture thereof.

10. Device according to any one of the preceding claims, comprising a support layer intended to be positioned in the gap (7) below the filling layer (11), preferably made of polyurethane foam.

11. Device according to any one of the preceding claims, in which the sealing coating (12) has, at a temperature of 55°C, a maximum elongation at break emax, expressed in %, with: Vma.v— / XIUU '0 where Dmax, expressed in mm, is a maximum relative movement allowed before breakage between the two adjacent assembly elements (2), l0, expressed in mm, is a width of the joint between the two assembly elements (2) adjacent, and cos y, unitless, is the cosine of the angle formed between the direction of relative movement between the two adjacent assembly elements (2) and the direction of the width of the joint between the two adjacent assembly elements (2).

12. System comprising at least two adjacent assembly elements (2) forming a seal and a sealing device (6) for said seal according to any one of the preceding claims.

13. System according to claim 12, in which the gap (7) comprises beveled edges (2c) forming a groove opening onto the surface of the assembly elements (2).

14. System according to claim 12 or 13, in which the assembly elements (2) are made of concrete.

15. System according to any one of claims 12 to 14, comprising a plurality of assembly elements (2) distributed into first sets (3) of assembly elements and second sets (4) of assembly elements comprising a smaller number of assembly elements than said first sets (3), said first and second sets (3, 4) being arranged alternately.

16. Dome intended to close a digester tank, comprising a plurality of adjacent assembly elements (2) each formed by a petal extending radially between the center of the dome (1) and the periphery of the dome (1), and comprising an even number of sealing devices (6) according to any one of claims 1 to 10 each sealing two adjacent assembly elements (2) of the plurality of assembly elements (2) to obtain a de-flush in the event of accidental overpressure within the digester.

17. Dome according to claim 16, in which each assembly element (2) comprises an outer face (2d) and an opposite inner face (2a), all of the inner faces (2a) of the assembly elements (2) forming an inner face of the dome (1) intended to be positioned opposite the interior of the digester, the inner face of the dome being coated with a sealing coating (16) arranged in continuity with the sealing coating (12) of the sealing device (6).

18. A method of obtaining a sealing device according to any one of claims 1 to 11, comprising a step of forming the filling layer and a step of forming the sealing coating, the step of forming the filling layer and / or the step of forming the waterproofing coating being carried out at least in part by projection from a projection machine.

Images