FR2753181A1 - LIQUID PRODUCTS STORAGE TANK - Google Patents

Abstract

The reservoir with double walls for storing liquid products is parallelepiped and rectangular, its sealed metal internal (2) and external (1) walls are fixed on either side of the metal frame (3) which is housed in the space of the double wall; the means for filling and emptying are located inside the parallelepiped volume of the reservoir and comprise at least connecting valves (10) for filling and emptying, fixed in a honeycomb (6) accessible and open on one side surface of the reservoir.

Description

Liquid product storage tank
The present invention relates to a storage tank for liquid products with double walls.

 The technical sector of the invention is the field of the production of receptacles for the storage and storage of materials, in particular liquids.

 One of the main applications of the invention is the storage of liquid fertilizers but also of any polluting, harmful, repulsive product, etc., and not under pressure, such as in the field of plant health, weedkillers, etc.

 To date and for such types of products, it is in fact used cisterns or other tanks of generally cylindrical shape of revolution, with single wall, which are placed in a bucket or a recovery tank for possible leaks, with filling valves located outside the wall of the tank and a drain placed at its lower part to recover the liquid by gravity.

 Such devices are not very secure, occupy a fairly large floor space and do not comply with the various legal provisions for environmental protection.

 Indeed, fertilizers in particular, because of their composition based on nitrate, phosphate and nitrogen, are very polluting, with a density of 1.4 to 1.5: in the event of a leak or spillage on the ground, these liquids penetrate very quickly into it and will flow into the lower part of the water tables where it is then very difficult to locate and recover them for treatment. There is therefore a need and an obligation to have a retention capacity for any tank of liquid liable to create water or soil pollution.

To partially meet these criteria, there are different types of double-walled tanks, some of which have been the subject of patent applications, such as
- Patent application FR 2,336,318, under German priority and published in June 1977, describes a buried storage tank with double walls for liquids constituting a danger for groundwater, such as fuel oil: it is a storage tank, the walls of which are preferably thermosetting material, of generally cylindrical shape of revolution and comprising between its walls a leakage control space filled with a permeable material such as synthetic resin concrete; such tanks are quite large compared to their storage capacity and have no possibility of recovering the liquid which has passed through the first wall and which would thus fill the space filled with said permeable material.

 Two other patent applications, application FR 2,362,059 published in February 1978 and application FR 2,594,098 published in August 1988, describe containers for storage or transport, one for collecting milk, the other for aggressive or special products, also thanks to a double envelope, but always separated by a layer of filling materials, of generally cylindrical shape of revolution and whose valves are located at the top, therefore difficult to access, also preventing stacking tanks on top of each other.

 However, the problem posed is to be able to produce storage tanks for polluting liquid products such as fertilizers, with a retention capacity capable of collecting this liquid in the event of a leak in the tank collecting it, and which must be then be able to control and recover; the storage volume must be maximum in relation to the external space requirement and it must be possible to stack several tanks at least when they are empty to reduce the space requirement on the ground; moreover, owing to the fact that such tanks are stored in places where mobile vehicles can pass which risk hanging the valves on passage, these must be able to be protected and include any device avoiding reversing and making a mistake between filling or emptying systems, while being easily accessible.

 A solution to the problem posed is a storage tank for liquid products with double walls, the shape of which, both inside and outside is a rectangular parallelepiped, the inside and outside walls are flat, metallic, waterproof and fixed on either side of the metal framework which is housed at least for the bottom and the lateral faces in the space delimited by the double walls; its filling and emptying members are located inside the parallelepiped volume of the tank and comprise at least connection valves for filling and emptying, fixed in a cell thus forming an appendage inside the storage tank, and accessible and open on a side face of the tank and also comprising a double wall.

 In preferred embodiments, said cell is closed by two doors each corresponding to a filling and emptying function respectively and said storage tank has four lifting lugs fixed outside of its four upper corners, which ears follow the forms each angle and around it forms a stop protruding above the upper surface.

 The result is a new type of double-walled storage tank for liquid products, responding to the problem posed and offering new possibilities in their use.

 Indeed, the realization in double watertight walls in fact constitutes two tanks, the external one of which completely envelops, at least below and laterally, the internal storage proper, its volume is therefore in fact greater than that thereof, which external envelope constitutes well then a capacity of retention in conformity with the French regulations following in particular the Ministerial Decree of March 1, 1993 relating to the taking away and consumption of water as well as to the discharges of any kind of the installations classified for the protection of the environment , subject to authorization, which requires that any storage of a liquid liable to create water or soil pollution must be associated with a retention capacity whose volume must be at least equal to 100% of the tank capacity.

 In addition, due to its parallelepiped shape, it offers the maximum volume available compared to the external dimensions and its flat base allows it to be installed without requiring other supports, while its upper surface also flat and having no organ filling and emptying or other appendage, can receive other storage tanks stacked on top of each other, since also at their lower part, it does not have any drainage nozzle, unlike many current tanks.

 The filling and emptying members being grouped at breast height and placed inside the volume, are protected by the latter and cannot therefore be hung by a machine passing nearby; moreover, the cell receiving said members being able to be closed by lockable doors, it is possible to control the use thereof and with particular designs of valve levers prohibit, for example, any closing of the door if said valves are not closed.

 Its entirely metallic and welded construction ensures all guarantees, subject of course to strength calculations of the materials known and not explained here since they can be performed by any person skilled in the art who determines the dimensional and qualitative samples of the sheets and profiles used and necessary for this, as well as the surface treatment necessary to resist the types of products to be stored.

 The dimensions of such parallelepiped tanks can be chosen in accordance with the standard dimensions of European road containers for example, in order to facilitate empty transport to bring them to any place where they will receive the product to be stored.

 We could cite other advantages of the present invention, but those mentioned above already show enough to prove its novelty and interest.

 The description and the attached figures represent an exemplary embodiment of the invention, but are in no way limiting: other embodiments are possible, within the scope and scope of this invention, in particular by changing the type of internal framework separating the double walls.

 Figure 1 is a perspective view of the framework of a storage tank according to the invention.

 Figure 2 is an external view of a storage tank according to the invention.

 Figure 3 is a partial exploded perspective view of a reservoir according to the invention, with in particular its filling and emptying circuits.

 Figure 4 is an external perspective view of two tanks such as that of Figure 2, stacked one above the other.

The shape, both interior and exterior, of said liquid storage tank is a rectangular parallelepiped whose overall exterior dimensions may be those of standard dimensions of containers of French and European road type, that is to say a width of 2,438 millimeters, a height of 2,591 millimeters and different lengths of 2,240, 3,160, 6,058, 8,960, 12,116 millimeters corresponding to a useful volume of storage in the internal tank of said corresponding tank, respectively of 10 m3, 15 m3, 30 m3, 45 m3 and 60 m3
The internal 2 and external 1 walls are metallic, welded continuously to form two sealed tanks fitted one inside the other, and fixed on either side of the metallic framework 3 such as that shown in FIG. 1, and which is then housed in the space 21 of the double walls as shown in FIG. 2, in solid lines for the external walls and in dotted lines for the internal walls thus delimiting the storage tank proper: the bottom 12 of the wall outer may be a smooth sheet of 3 millimeters, the outer side walls 11 may also be sheets of 3 millimeters thick and ribbed like the side walls of known containers for transporting dry products with doors with full lateral opening, these ribs allowing to better withstand possible side impacts; the upper wall 13 can be simple since there is no need in this place where there can be no liquid retention, double wall and is then fixed on one of the sides of the frame 3, preferably the outer side, with a thickness of 2 millimeters.

 The inner bottom wall 22 constituting the bottom of the actual storage tank, as well as the inner side walls 2 can be 4 millimeters thick.

 According to the embodiment of Figure 1, the metal frame 3 comprises four corner posts and eight heddles forming the upper and lower frames 4: these posts and heddles are made with the same section of profile, for example a tube square with a side of 120 millimeters and a thickness of 4 millimeters, the external dimensions of which, e = 120 millimeters, are at least equal and preferably greater than the thickness e 'of the space 21 left between the double walls 1, 2 which are welded to their periphery.

 Furthermore, to stiffen and hold said double walls, the metal frame 3 further comprises connecting members 5, some parallel to the corner posts 42 for the lateral faces and connecting the upper and lower frames, and others parallel to the smallest side of the upper and lower faces in which they are located: their external dimensions of section of section are smaller than those of the posts and beams 4 and they receive in support the external walls 1 and internal 2 which sandwich them ; the space 21 then has exactly the thickness e ′, the height of the profile of these members 5 which are also welded therein at least for the external walls 11 such as by point and plugging from the outside once assembled; the internal walls 2 being welded beforehand against the members 5 before the installation of the external walls.

Said members 5 can be made of type beams
HEA of 100 millimeters in height between the soles, which determines a thickness e 'of the space 21 between the double walls 1, 2 of 100 millimeters also.

 Said storage tank has on its upper surface and opening on its upper wall 13 a manhole 20 or inspection hatch whose support frame is located inside the volume of said reservoir so that the upper part of the hatch access does not exceed said upper surface.

 To also reinforce the double walls of the bottom, this can include a longitudinal beam, crossing perpendicularly in their middle the members 5 of the bottom, as shown in FIG. 1.

 Four lifting ears or lugs 7 are fixed outside the four upper corners of the tank, which ears follow the shape of each angle and constitute around it a stop protruding above the upper surface 13: such lifting lugs 7 thus allow on the one hand the handling from above with slings from a gantry or other crane for lifting said tanks, and on the other hand because of their particular arrangement in the corners, to receive the lower corners of another similar container that we would like to stack on top, as shown in Figure 4.

 Other lifting lugs can also be added along the lateral external walls 11 and also protruding from the upper wall 13 If necessary for lifting the long tanks; similarly under the bottom 12 or by taking advantage of the double thickness of the double bottom, it is possible respectively to make elevations or cells allowing it to be able to slide lifting systems from below such as by forks.

 According to the representation in FIG. 3, the filling and emptying members are located inside the parallelepiped volume of the tank and comprise at least connection valves 10 fixed in a cell 6 accessible and open on a side face of the tank, preferably one of the smallest in the case of a rectangular parallelepiped.

 Said cell 6 is closed from the outside by two lockable doors 8 l and 82 each corresponding to a filling and emptying function respectively: thus, the use of such a tank can be personalized by having specific keys, on the one hand several identical to access the emptying part by the operators who come to take the liquid stored in the tank and on the other hand another for the Company delivering said liquid and which is then the only one able to access the filling part; such a provision also prohibits any false operation and the possibility of designing levers prohibiting any closing of the door when the valves are not closed, completes the safety measures for users; such valve devices are not specifically shown in Figure 3 but can be made by any person skilled in the art. In addition, each valve 10 can be specific and include personalized keying fittings, in order to be usable by a single type of user and / or delivery company having compatible fittings, which allows everyone to properly control the use and the type of product that can be stored in said tank.

 The filling circuit 12 from the corresponding filling valve, opens at the upper inner part 18 of the tank and includes a non-return valve 14: the filling is then done in rain from the top of the storage tank, while the emptying is done by aspiration through a dip tube, the end of which is located in a drawing-off bowl 16 produced through and below the internal wall 22 of the bottom of the storage tank where this bowl 16 opens, and in the 'space e' of the double bottom. Said drainage circuit 13 also comprises a non-return valve 14 and at least one part in the form of a swan neck 17 facing the upper part of said tank requiring good suction in order to be able to draw the liquid which one wants to use, which is additional safety in use. This swan neck arrangement also provides security in the event of the drain valve 10 breaking.

 Each filling 12 and drain 13 circuit respectively, includes a purge valve 11 for recovering any liquid remaining in the pipes after use thereof.

 One or more vents 15 of the storage tank and of the double wall are also produced in the upper part of the tank and open laterally so as not to protrude from the upper wall 13.

 Said tank also comprises at its lower part a control valve 19 and emptying of the double wall, in order to be able to detect and then recover any liquid which could have flowed there in the event of failure of the walls of the internal storage tank.

Claims (10)

 1. Double-walled liquid product storage tank, characterized in that its interior and exterior shape is a rectangular parallelepiped, its interior (2) and exterior (1) walls are flat, metallic, watertight and fixed on one side and other of the metal frame (3) which is housed at least for the bottom and the side faces in the space (21) delimited by the double walls.  2. Storage tank according to claim 1, characterized in that its filling and emptying members are located inside the parallelepiped volume of the tank and comprise at least connection valves (10) for filling and emptying, fixed in a cell (6) accessible and open on a side face of the tank.  3. Tank according to claim 2, characterized in that said cell (6) is closed by two doors (8l, 82) each corresponding to a filling and emptying function respectively.  4. Tank according to any one of claims 2 or 3, characterized in that the filling circuit (12) opens at the upper part (18) inside the tank.  5. Reservoir according to any one of claims 2 to 4, characterized in that the emptying circuit (13) comprises at least one part in the form of a swan neck (17), turned towards the upper part of the reservoir and its end is located in a drawing bowl (16) made in the double bottom.  6. Tank according to any one of claims 1 to 5, characterized in that the upper wall (13) is simple and fixed on one of the sides of the frame (3).  7. Tank according to any one of claims 1 to 6, characterized in that at least the external walls of the side faces (12) are ribbed.  8. Tank according to any one of claims 1 to 7, characterized in that it comprises four lifting lugs (7) fixed to the outside of its four upper angles, which lugs (7) conform to the shape of each angle and constitute around it a stop protruding above the upper surface (13).  9. Tank according to any one of claims 1 to 8, characterized in that the metal frame (3) comprises four corner posts and eight smooth forming the upper and lower frames (4), made with the same section of profiled and whose external dimensions are at least equal to the thickness of the space (21) of the double walls (1, 2) which are welded to their periphery.  10. Tank according to claim 9, characterized in that the metal frame (3) comprises members (5) for connection, some parallel to the corner posts (42) for the lateral faces and connecting the upper and lower frames , and others parallel to the smallest side of the upper and lower faces in which they are located, their external dimensions of section of section being smaller than those of the posts and beams (4) and they receive in support the external walls (1 ) and internal (2) which sandwich them.