Device for sealing a storage tank opening

Abstract

Device for sealing a storage tank opening The invention relates to a device for sealing a storage tank opening (11) for contents likely to be at high pressure, characterized in that the device comprises: a circular cylindrical neck (12) positioned on the wall of the tank so that the inner surface of the neck surrounds the tank opening, the inner surface of the cylindrical neck comprising at least two threads (13) arranged through the thickness of the neck, a circular cylindrical cap (2) of dimensions complementary to the neck, this cap incorporating at least one seal (21) on its peripheral face which is configured to bear against the inner surface of the neck when the cap is positioned in the neck,the peripheral surface of the cap comprising at least two nipples (23) positioned between them so as to cooperate individually with a respective thread (13) of the neck. Figure to be published with the abstract: Fig.3,

Description

Title of the invention: Device for sealing a storage tank opening

[0001] The present invention relates to the field of storage tanks and more particularly to the field of mechanisms for sealing the openings of these tanks.

[0002] Conventionally, storage tank openings are made at the level of structures welded to the tanks which have the shape of a tube whose end forms an orifice of substantially cylindrical shape. This welded construction makes it possible in particular to meet resistance constraints at storage pressures of several bars, sometimes even up to twenty bars. Current closure systems notably involve a cast iron counter-flange which forms a cap for covering the opening carried by the tube and at least part of its peripheral surface. In order to ensure a seal when positioning the counter-flange on the end of the tube, the counter-flange incorporates a stainless steel disc at its inner surface.This stainless steel disc has dimensions slightly larger than the tube opening so as to allow the pinching of a flat gasket against a surface or a lip of the edge of the tube opening and to avoid any contact of the contents of the tank with the cast iron of the counter-flange. The holding of the cap in position and the tightening of the flat gasket in pinching between the disc and the tube are ensured by the cooperation of a thread carried by the peripheral surface of the tube with a complementary thread carried by the internal surface of the cap which functions as a ring surrounding the end of the tube. Such a solution, if it is effective in ensuring a seal, requires the tightening of the flat gasket by the counter-flange on the edge of the cylindrical orifice. Also, the quality of the seal is determined by the extent to which the counter-flange is tightened on the tank.Furthermore, due to the clamping mechanism it requires, such a counter-flange creates a bulky structure which may be cumbersome at the tank opening.

[0003] The present invention aims to overcome these drawbacks by proposing a technical solution whose construction allows the opening orifice of a tank to be closed and its watertight locking to be independent of a tightening parameter of a closing structure such as a counter-flange on the opening of the tank, while proposing a particularly restricted size at the level of the orifice of the tank.

[0004] The invention thus relates to a device for sealing a storage tank opening for contents likely to be at high pressure, characterized in that the device comprises: - a circular cylindrical neck positioned on the wall of the tank so that the inner surface of the neck surrounds the opening of the tank, the inner surface of the cylindrical neck comprising at least two threads arranged through the thickness of the neck, - a circular cylindrical stopper with dimensions complementary to the neck, this stopper incorporating at least one seal on its peripheral face which is configured to bear against the interior surface of the neck when the stopper is positioned in the neck, the peripheral surface of the stopper comprising at least two pins positioned between them so as to cooperate individually with a respective thread of the neck.

[0005] The invention will be better understood from the following description, which relates to a preferred embodiment, given as a non-limiting example, and explained with reference to the appended schematic drawings, in which:

[0006] [Fig-1] represents a schematic illustration according to a sectional view of a example of a tank opening comprising a closing device of the invention,

[0007] [Fig.2] represents a schematic illustration of a first example of a closing device closure of the invention,

[0008] [Fig.3] represents a schematic illustration of a second example of a device of closure of the invention,

[0009] [Fig.4] represents a schematic illustration of an example of a cylindrical neck circular participating in the production of a closing device of the invention,

[0010] [Fig.5] represents a schematic illustration, according to a sectional view and according to a side view of one of the faces, of an example of a circular cylindrical plug participating in the production of a closing device of the invention.

[0011] The invention relates to a device for sealing an opening 11 of a storage tank 1 for contents likely to be at high pressure, characterized in that the device comprises: - a circular cylindrical neck 12 positioned on the wall of the tank 1 so that the inner surface of the neck 12 surrounds the opening 11 of the tank 1, the inner surface of the cylindrical neck 12 comprising at least two threads 13 arranged through the thickness of the neck 12, - a circular cylindrical stopper 2 of dimensions complementary to the neck 12, this stopper 2 integrating at least one seal 21 on its peripheral face which is configured to bear against the interior surface of the neck 12 when the stopper 2 is positioned in the neck 12, the peripheral surface of the stopper 2 comprising at least two pins 23 positioned between them so as to cooperate individually with a respective thread 13 of the neck 12.

[0012] Such a closing device makes it possible to seal the opening 11 of the neck 12 by pinching the seal 21 between the peripheral edge of the cap 2 and the inner surface of the neck 12 without the quality of the closing being linked to the force of the tightening of the cap 2 at the neck 12. The only complementarity of shape in a plane in section at the neck 12 of the tank 1 is sufficient to pinch the seal 21 between the cap 2 and the inside of the neck 12 so that the compression carried out in pincers of the seal 21 between these two elements 2, 12 seals the mounting of the cap 2 on the tank 1.

[0013] The locking of the cap 2 with the neck 12 of the reservoir 1 involves the cooperation of the at least two studs 23 of the cap 2 with the threads 13 of the reservoir 1, each of the studs 23 being guided in sliding along the length of a respective thread 13. Each thread 13 has a grooved arrangement which allows the guiding of a stud 23 in movement along a stroke similar to that of at least a portion of a screw thread, during an axial pivoting of the cap 2 around an axis passing through the center of the circular opening 11 of the neck 12. The grooving of the threads 13 is formed passing through the thickness of the neck 12 so that, preferably, a stud 23 positioned through a thread 13 has an end which can be manipulated from the peripheral outer face of the neck 12.

[0014] According to an example relating to a construction variant, the threads 13 of the neck 12 and the pins 23 of the cap 2 are distributed so that their respective barycenters are positioned on the axis of the cylinder of the neck 12. According to such a configuration, the pins 23 and threads 13 are distributed on the periphery of the cap 2 so as to obtain a homogeneous distribution of the anchoring points of the cap 2 on the neck 12 and to achieve a substantially uniform hold at the periphery of the cap 2.

[0015] Preferably, the pins 23 are positioned on the periphery of the plug 2, radiating radially from the center of the plug 2 in a symmetrical distribution around the pivot axis of the plug 2. However, a different distribution could be envisaged.

[0016] According to an example relating to a particular variant embodiment of the studs 23 and capable of being combined with one or other of the previously detailed variants, these have a substantially flattened arrangement by being arranged along a length of the peripheral edge of the cap 2. This arrangement thus allows insertion and sliding of the studs 23 along the respective threads 13 while preventing any risk of tilting or pivoting of the cap 2 around an axis of the plane of the cap 2 when the latter is equipped with only two studs 23 arranged in alignment with the pivot axis of the cap 2 relative to the neck 12.

[0017] According to an example relating to another variant of the closing device of the invention and capable of being combined with one or other of the variants pre previously detailed, the at least two threads 13 of the neck 12 comprise, on the one hand, a first end 131 open at the end rim of the neck 12 and, on the other hand, a second closed end 132 defining an end of travel of the pins 23 of the cap 2, the second ends 132 of the threads 13 comprising a respective housing 133 made so that these housings 133 have an edge closer to the end rim of the neck 12 compared to the juxtaposed edge of a portion of the travel of the thread 13 near the housing 133 which is further from the end rim of the neck 12. It should be noted that the dimensions of the housing 133 are adapted to receive a pin 23 of the cap 2. Such a housing 133 at the end of the thread 13 thus allows the reception and positioning of a pin 23 arrived at the end of the course of its sliding along the net 13.

[0018] The construction of the housing 133 so that one of its edges is closer to the end rim of the neck 12 than the juxtaposed edge of a portion of the travel of the thread 13 near the housing 133 creates a relief or a retaining corner of the stud 23 in the housing 133. Thus, during its movement along the thread 13, in particular when the contents of the reservoir 1 have a pressure greater than the external pressure, the studs 23 of the cap 2 bear against the edges of the threads 13 and of the respective housings 133 closest to the end rim of the neck 12. Before reaching the end of its travel when inserted into the housing 133, the stud 23 is moved to bear against the edge of the relief or retaining corner positioned at the junction between the housing 133 and the rest of the thread 13.Also, once the nipples 23 are inserted into their respective housings 133, under the effect of the internal pressure of the reservoir, the cap 2 positions the nipples 23 in abutment against the respective edges of the housings 133 closest to the end edges of the neck 12. Each nipple 23 is thus held against an edge of the housing 133, blocked in displacement between, on the one hand, the second closed end 132 of the thread 13 and, on the other hand, the relief produced by the retaining corner of the nipple 23 to limit, or even prevent, its accidental displacement in the direction of the first open end 131 of the thread 13. Also, the cooperation of the nipple 23 with the retaining corner during its displacement along the thread 13 corresponds substantially to that of a phenomenon of clipping the cap 2 with the neck 12.

[0019] According to an example relating to another variant of the closure device of the invention and capable of being combined with one or other of the previously detailed variants, the at least two threads 13 of the neck 12 comprise, on the one hand, a first end 131 open at the end rim of the neck 12 and, on the other hand, a second closed end 132 defining an end of travel of the pins 23 of the cap 2, the threads 13 comprising an end of travel portion incorporating a housing 133 arranged in a plane substantially perpendicular to the axis of the cylinder. of the neck 12. This orientation of the housing 133 at the end of the thread 13 is configured to position the cap 2 in the neck 12 according to an arrangement corresponding to a definitive and optimal position for the sealed locking of the cap 2 with the neck 12 as soon as the pins 23 come into abutment against the ends of the housings 133 corresponding to the closed ends 132 of their respective threads 13. This particular orientation of each of the housings 133 thus has an inclination relative to the stroke of the rest of the thread 13 associated with it. Indeed, the threads 13 have a main portion of stroke from their first open ends 131 at the end edge of the neck 12 arranged according to a stroke similar to that of at least a portion of a screw thread.Also, the threads 13 have a deviation of their courses at the respective junctions between, on the one hand, the housings 133 and, on the other hand, the main portions of the courses of the threads 13, so that this deviation shows an inclination between the two portions of the threads 13. The deviation between the two portions of the course of the threads 13 is likely to have the shape of a curvature or that of one or more angles similar to that of a broken arc. It is however imperative that the widths of the threads 13 at the respective deviations are sufficiently wide to ensure the efficiency of the movement of the pins 23 along the threads 13 when crossing the junctions between the two portions of the threads 13.

[0020] According to an example relating to another variant of the closure device of the invention and capable of being combined with one or other of the previously detailed variants, the cap 2 comprises a reinforcing structure 22 opposing its deformation under the effect of pressure exerted from inside the storage tank 1. This reinforcing structure 22 is in particular arranged according to a distribution which operates a stiffening of at least a part of the central portion of the cap 2, that is to say of the portion located at the axial pivot axis of the cap 2, with at least a part of the peripheral portion of the cap 2. This reinforcing structure 22 is thus configured to prevent any displacement in height of the central portion of the cap 2 relative to its peripheral portion, that is to say any variation in position along an axis substantially parallel to the pivot axis of the cap 2.

[0021] According to an example relating to a specific variant of the previous variant of the closure device of the invention, the reinforcement structure 22 of the cap 2 is made by an overmolded metal core. As an example of construction, the metal core has a planar arrangement. Such an arrangement facilitates the positioning and integration of the reinforcement structure 22 in the thickness of the cap 2 by limiting its size. According to an alternative example of construction, the metal core has a construction comprising a convex arrangement to be positioned in direction of the surface of the cap 2 intended to face the interior of the tank 1. This convexity of the reinforcement structure 22 and its particular orientation thus make it possible to optimize the distribution of forces and stresses inside the cap 2 in the context of forces exerted by possible pressure coming from inside the tank 1. Thus, in the event of excessive pressure likely to deform the reinforcement structure 22, the convexity operates a distribution of the stresses supported so that the forces supported in the central part of the structure are oriented towards the periphery of the reinforcement structure 22. The forces redirected at the peripheral edge of the cap 2 increase the pressure exerted by the seal 21 against the inner wall of the neck 12. The sealing capacity of the cap 2 to the tank 1 is then increased.Also by way of example, the metal core is arranged in the thickness of the plug 2 and may have the form of a solid structure configured to correspond to the essential part if not the whole of the plug 2 in section. According to an alternative construction, the reinforcement structure is produced in the form of a mesh or grilled structure. Such a construction allows for a more intimate integration of the metal reinforcement structure with the material specific to the rest of the plug 2, the material of the plug 2 being distributed through the meshes and opening of the grille. By way of example, this mesh or grille has a star arrangement of which different branches radiate from the central part towards the peripheral part of the plug 2. The radial ends of these different branches are also likely to be joined by a peripheral junction corresponding for example to the line of a circumscribed circle of the star.

[0022] According to an example relating to another specific variant and capable of being combined with the previously detailed variant, the reinforcement structure 22 of the plug 2 is produced by at least one relief which has the shape of a bead at the level of the thickness of the plug 2. This reinforcement structure 22 is thus formed by an excess thickness located at the level of one of the surfaces of the plug 2 along an axis substantially parallel to the pivot axis of the plug 2. By way of example, this relief is capable of having a star arrangement of which different branches radiate from the central part in the direction of the peripheral part of the plug 2, the central part of the plug 2 also being capable of comprising a thickness.The radial ends of the different branches formed by ridges are also likely to be joined at the periphery by a ridge arranged along a circumscribed circle of the star and which operates the junction of the branches.

[0023] According to an example relating to another specific variant and capable of being combined with the previously detailed variants, the reinforcement structure 22 is extended at the level of each of the studs 23 of the cap 2. This construction of the reinforcement structure 22 up to the studs 23 allows reinforcement of the studs 23 which, in providing the mechanical junction between the cap 2 and the reservoir 1, correspond to a portion of the cap 2 supporting high stresses. This particular construction of the reinforcement structure 22 also makes it possible to distribute the forces and stresses supported by the cap 2 to the neck 12, so that the forces supported by the cap 2 are transmitted, in particular along the reinforcement structure 22, to the structure of the reservoir 1.

[0024] According to an example relating to another variant of the closure device of the invention and capable of being combined with the previously detailed variants, the cap 2 has a convex arrangement intended to be oriented towards the interior of the storage tank 1 so as to reinforce its resistance to deformation under the effect of pressure exerted from inside the storage tank 1. This convexity of the cap 2 and its particular orientation make it possible to optimize the distribution of forces and stresses inside the cap 2 in the event of forces exerted by pressure exerted from inside the tank 1. Indeed, the convexity of the cap 2 distributes the stresses supported so that the forces present at the central part of the cap 2 are directed towards the periphery of the cap 2.The redirection of forces at the peripheral edge of the cap 2 is thus likely to increase the pressure exerted by the seal 21 against the inner wall of the neck 12. The sealing capacity of the cap 2 to the reservoir 1 is then increased.

[0025] According to an example relating to another variant of the closure device of the invention and capable of being combined with the previously detailed variants, the surface of the cap 2 intended to be oriented towards the outside of the storage tank 1 has an actuation interface 24 rotating around the axis of the cylinder of the neck 12. According to an example of construction, this actuation interface 24 is produced by the end of at least one stud 23 of the cap 2 which passes through the neck 12 at the level of a thread 13. This stud end 23 is thus capable of producing a manipulation arm to operate the pivoting of the cap 2 around its axis of insertion in the neck 12.According to another example of construction that may be an alternative or complementary to the previous one, the actuation interface 24 comprises an interface which, in a plane parallel to the plane of the cap 2, has a polygonal shape centered on the pivot axis of the cap 2 or its axis of insertion into the neck 12. This polygonal interface is thus able to cooperate with a complementary interface of a tool for actuation of the cap 2. As an example of construction, the polygonal interface is of the hexagonal type similar to the peripheral surface of a bolt. According to another example of construction that may be an alternative or complementary to the previous ones, the actuation interface 24 comprises a manual interface integrated into the surface of the cap 2, for example in the form of a pair of fins similar to those of a nut. butterfly, these fins being arranged symmetrically on either side of the pivot axis of the cap 2 or of its insertion axis in the neck 12.

[0026] According to an example relating to another variant of the closure device of the invention and capable of being combined with the previously detailed variants, the cap 2 comprises at least one through-orifice 25 of which at least one opening 251 is configured to bear, directly or indirectly, against one end of a conduit 3. Such an orifice 25 through the cap 2 allows the positioning of a conduit 3 mounted through the cap 2. Such a conduit 3 is preferably rectilinear and is capable of corresponding to a glove finger to allow the insertion of different sensors for the measurement of different parameters inside the tank 2. Preferably, the conduit 3 has a cross-sectional diameter substantially identical to, if not slightly smaller than, the cross-sectional diameter of the through-orifice 25 or of the opening 251 of this through-orifice 25.According to a particular example of construction, the through-orifice 25 is positioned in the center of the cap 2, so that the conduit 3 inserted through this orifice 25 is coaxial with the pivot axis of the cap 2 relative to the neck 12. When the cap 2 comprises an actuation interface 24 of polygonal shape, the through-orifice 25 is thus likely to be centered on this actuation interface 24. According to an example of construction, the conduit 3 is fixed directly to the cap 2 at the periphery of the opening 251 of the through-orifice 25 to form a single structural assembly with the cap 2. Such a construction makes it possible to avoid any sealing defect between the cap 2 and the peripheral surface of the conduit 3. According to a preferred alternative construction, the conduit 3 corresponds to a structure independent of the cap 2.The peripheral surface of the conduit 3 is then in tight contact, directly or indirectly, with the periphery of the opening 251 of the through-orifice 25 of the plug 2 so as to prevent any sealing problem likely to arise between the plug 2 and the peripheral surface of the conduit 3.

[0027] According to an example relating to a specific variant of the preceding variant of the closure device of the invention, the interaction between the through-orifice 25 and the conduit 3 comprises an intermediate circular seal 252 centered on the axis of the opening 251 of the through-orifice 25 and the conduit 3. This circular seal 252 is capable of being positioned at the level of the entire height of the interaction between the through-orifice 25 and the conduit 3 so that there is no direct contact between the through-orifice 25 and the conduit 3. The circular seal 252 thus provides a compressed intermediate interface between the through-orifice 25 and the conduit 3 so as to ensure a seal between the plug 2 and the peripheral surface of the conduit 3. According to an alternative arrangement, the circular seal 252 is positioned at the level of a portion of the height of the interaction between the through-orifice 25 and the conduit 3 so that, of a On the one hand, a first part of the conduit 3 is in direct contact with the plug 2 at the through-orifice 25 and, on the other hand, a second part of the conduit 3 is in indirect contact with the plug 2 via the circular seal 252. The circular seal 252 clamped between the plug 2 and the peripheral surface of the conduit 3 ensures the seal between these two elements 2, 3. Preferably, the circular seal 252 is positioned in a housing 253 arranged at the periphery of the opening 251 of the through-orifice 25. This housing 253 has at least one opening oriented towards the axis of the through-orifice 25 or of the conduit 3. In a complementary manner, this housing 253 is capable of being produced in the form of a shoulder sized to receive the circular seal 252 and positioned in a circular manner at the inner edge of the through-orifice 25 or one of its openings 251.

[0028] According to an example relating to another specific variant and capable of being combined with the previously detailed variant, the interaction between the through-orifice 25 and the conduit 3 involves a flange 31, a thread 32 or a weld. By way of example, one of the ends of the conduit 3 is associated with a flange 31 to which it is fixed. The flange 31 is then configured to cooperate with a surface, preferably the outer surface, of the plug 2 located around one of the openings of the through-orifice 25, for example by a complementarity of shape between a surface of the flange 31 and a relief carried by the surface of the plug 2. Also, when inserting the conduit 3 into the tank 1 through the through-orifice 25 of the plug 2, the flange 31 in contact with the outer surface of the plug 2 creates a stop which makes it possible to block the insertion stroke of the conduit 3 and prevents the conduit 3 from falling inside the tank 1.According to another example that can be combined with the previous example, a part of the peripheral surface of the conduit 3 or of the flange 31 comprises a thread 32 whose pitch is complementary to a thread carried by the inner wall of the through-orifice 25 of the plug 2. Also, the conduit 3 is capable of being mounted and assembled with the plug 2 by direct screwing with the through-orifice 25 during its insertion through the plug 2 or by indirect screwing by means of a flange 31 to which the conduit 3 is fixed. According to another example that can be an alternative to the two previous examples, an orifice at the end of the conduit 3 has a lip 33 whose cross-sectional diameter is greater than the cross-sectional diameter of the rest of the conduit 3.This lip 33 is configured to cooperate with a shoulder 253 carried by the inner wall of the through-orifice 25, either directly or indirectly by means of a circular seal 21 housed at the level of this shoulder 253, the circular seal 21 surrounding the conduit 3 at the level of the peripheral surface of its end lip 33. The cross-sectional diameter of the inner wall of the through-orifice 25 at the level of the shoulder 253 is less than the cross-sectional diameter of the lip 33 of the conduit 3. The cooperation of . the lip 33 at the end of the conduit 3 with the shoulder 253 of the through-orifice 25 thus operates a blocking of the conduit 3 with the plug 2 in its travel through the through-orifice 25. The maintenance of the lip 33 of the conduit 3 against the surface of the shoulder 253 is also capable of being completed by the positioning of a flange 31 bearing against the surface of the lip 33 of the conduit 3 opposite the shoulder 253, this flange 31 allowing the clamping of the conduit 3 by its lip 33 with the through-orifice 25 of the plug 2. In a complementary manner, the flange 31 is capable of allowing the clamping by means of a thread 32 which cooperates with a complementary thread carried by a portion of the inner wall of the through-orifice 25 located above the shoulder 253 in interaction, directly or indirectly, with the lip 33 of the conduit 3.The actuation of the pivoting of the flange 31 relative to the through-orifice 25 of the plug 2 for the tightening of the lip 33 of the conduit 3 against the shoulder 253 of the orifice 25 is capable of being carried out by means of a rotational actuation interface 24 for the operation of screwing the flange 31 into the through-orifice 25, for example by means of a polygonal interface capable of cooperating with a complementary interface of a tool.

[0029] According to an example relating to another variant capable of being combined with several of the previously detailed variants, the interaction between the through-orifice 25 and the conduit 3 is carried out at the surface of the plug 2 intended to be oriented towards the interior of the storage tank 1. By being carried out at the interior surface of the plug 2, the assembly and installation of the conduit 3 on the plug 2 directly or by means of a possible flange 31 must be carried out prior to the installation of the plug 2 on the opening 11 of the tank 1.

[0030] According to an example relating to another variant capable of being combined with several of the previously detailed variants and forming a construction alternative to the previously detailed variant, the interaction between the through-orifice 25 and the conduit 3 is carried out at the surface of the plug 2 intended to be oriented towards the outside of the storage tank 1, the conduit 3 being mounted through the through-orifice 25 of the plug 2. By being carried out at the interior surface of the plug 2, the mounting and installation of the conduit 3 on the plug 2 directly or by means of a flange 31 are then capable of being carried out before or after the installation of the plug 2 on the opening 11 of the tank 1.

[0031] According to an example relating to another variant capable of being combined with several of the previously detailed variants, the peripheral edge of the cap 2 comprises a shoulder 26 which carries the peripheral seal 21, the shoulder 26 being at a distance from the external surface of the cap 2 so that the peripheral seal 21 is spaced, on the one hand, from the outer surface of the cap 2 and, on the other hand, from the rest of the peripheral surface of the cap 2. The peripheral seal 21 of the cap 2 is then carried by the peripheral surface of the shoulder 26. This arrangement allows the creation of a spacing 4 between, on the one hand, a part of the inner wall of the neck 12 arranged in contact, or even close to, the outer orifice of the neck 12 and, on the other hand, the peripheral edge of the cap 2 which does not carry the shoulder 26. The distance between the shoulder 26 and the outer surface of the cap 2 then allows this spacing 4 to be open at the level of the outer orifice of the neck 12. Such a spacing 4 thus allows the positioning of an element 5 fixed by clipping at the level of at least a part of the edge of the neck 12 without the presence of the cap 2 in the cylindrical opening 11 of the neck 12 does not interfere with the positioning of a clipping element at the level of the inner wall of the neck 12.The spacing 4 thus allows accessibility of the inner wall of the neck 12 at a greater portion of the height thanks to the spaced positioning of the peripheral seal 21 by the shoulder 26 of the cap 2.

[0032] Of course, the invention is not limited to the embodiment described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Device for sealing an opening (11) of a storage tank (1) for contents likely to be at high pressure, characterized in that the device comprises: - a circular cylindrical neck (12) positioned on the wall of the tank (1) so that the inner surface of the neck (12) surrounds the opening (11) of the tank (1), the inner surface of the cylindrical neck (12) comprising at least two threads (13) arranged through the thickness of the neck (12), - a circular cylindrical cap (2) of dimensions complementary to the neck (12), this cap (2) integrating at least one seal (21) on its peripheral face which is configured to bear against the inner surface of the neck (12) when the cap (2) is positioned in the neck (12),the peripheral surface of the cap (2) comprising at least two nipples (23) positioned between them so as to cooperate individually with a respective thread (13) of the neck (12).,

2. Device for sealingly closing an opening (11) of a tank (1) according to claim 1, characterized in that the at least two threads (13) of the neck (12) comprise, on the one hand, a first end (131) open at the end rim of the neck (12) and, on the other hand, a second closed end (132) defining an end of travel of the pins (23) of the cap (2), the second ends (132) of the threads (13) comprising a respective housing (133) made so that these housings (133) have an edge closer to the end rim of the neck (12) than the juxtaposed edge of a portion of the travel of the thread (13) near the housing (133) which is further away from the end rim of the neck (12).

3. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the at least two threads (13) of the neck (12) comprise, on the one hand, a first end (131) open at the end edge of the neck (12) and, on the other hand, a second closed end (132) defining an end of travel of the pins (23) of the cap (2), the threads (13) comprising an end of travel portion incorporating a housing (133) arranged in a plane substantially perpendicular to the axis of the cylinder of the neck 12.

4. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the cap (2) comprises a reinforcing structure (22) opposing its deformation under the effect of pressure exerted from inside the storage tank (1).

5. Device for sealing an opening (11) of a tank (1) according to claim 4, characterized in that the reinforcing structure (22) of the cap (2) is produced by an overmolded metal core.

6. Device for sealing an opening (11) of a tank (1) according to one of claims 4 or 5, characterized in that the reinforcing structure (22) of the cap (2) is produced by at least one relief which has the shape of a bead at the level of the thickness of the cap (2).

7. Device for sealing an opening (11) of a tank (1) according to one of claims 4 to 6, characterized in that the reinforcing structure (22) is extended at the level of each of the nipples (23) of the cap (2).

8. Device for sealing an opening (11) of a tank (1) according to one of claims 4 to 7, characterized in that the cap (2) has a convex arrangement intended to be oriented towards the inside of the storage tank (1) so as to reinforce its resistance to deformation under the effect of pressure exerted from inside the storage tank (1).

9. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the surface of the cap (2) intended to be oriented towards the outside of the storage tank (1) has an actuating interface (24) rotating around the axis of the cylinder of the neck (12).

10. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the cap (2) comprises at least one through orifice (25) of which at least one opening (251) is configured to bear, directly or indirectly, against one end of a conduit (3).

11. Device for sealing an opening (11) of a tank (1) according to claim 10, characterized in that the interaction between the through-orifice (25) and the conduit (3) comprises a circular seal (252) intermediate centered on the axis of the opening (251) of the through orifice (25) and of the conduit (3).

12. Device for sealing an opening (11) of a tank (1) according to one of claims 10 and 11, characterized in that the interaction between the through-orifice (25) and the conduit (3) involves a flange (31), a thread (32) or a weld.

13. Device for sealing an opening (11) of a tank (1) according to one of claims 10 to 12, characterized in that the interaction between the through-orifice (25) and the conduit (3) is carried out at the surface of the cap (2) intended to be oriented towards the interior of the storage tank (1).

14. Device for sealing an opening (11) of a tank (1) according to one of claims 10 to 13, characterized in that the interaction between the through-orifice (25) and the conduit (3) is carried out at the surface of the cap (2) intended to be oriented towards the outside of the storage tank (1), the conduit (3) being mounted through the through-orifice (25) of the cap (2).

15. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the peripheral edge of the cap (2) comprises a shoulder (26) which carries the peripheral seal (21), the shoulder (26) being at a distance from the outer surface of the cap (2) so that the peripheral seal (21) is spaced, on the one hand, from the outer surface of the cap (2) and, on the other hand, from the rest of the peripheral surface of the cap (2).

16. Device for sealing an opening (11) of a tank (1) according to one of the preceding claims, characterized in that the threads (13) of the neck (12) and the nipples (23) of the cap (2) are distributed so that their respective barycenters are positioned on the axis of the cylinder of the neck (12).

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