WO2000064787A1

WO2000064787A1 - Silo for storage and regulated supply of light empty bottles and method for the utilization thereof

Info

Publication number: WO2000064787A1
Application number: PCT/ES1999/000108
Authority: WO
Inventors: Jaime Marti Sala
Original assignee: Jaime Marti Sala
Priority date: 1999-04-23
Filing date: 1999-04-23
Publication date: 2000-11-02
Also published as: AR023755A1

Abstract

The silo comprises a deposit (1) with an top loading inlet (2) and a bottom (3) with a regulatable discharge hole (3a), whose deposit (1) is subdivided into superimposed compartments (B) that can be filled by gravity, whose height (H) is a function of the resistance of the type of bottle (A) to be stored, said compartments (B) being defined by retractable support planes (4) fitted with means for independent actuation which can displace the latter by opening or closing at least one passage for unloading the bottles (A) from one compartment to the next lowest compartment (A) provided that the latter is totally or partially empty or not communicating with the next lower compartment and excepting the compartment located at the lowest level, wherein the discharge hole (3a) can be closed or open.

Description

SILO FOR STORAGE AND REGULATED SUPPLY OF EMPTY LIGHT PACKAGES. AND METHOD FOR ITS USE Scope of the invention

The present invention concerns a silo for storage and regulated supply of empty light packages, and more particularly a silo capable of being loaded by a top loading inlet and capable of supplying the packages by gravity from a lower outlet, suitable for being used, for example, as a maintenance and regulated feeding tank for empty containers, in particular plastic containers, but not limited to a bottling line, or as a temporary storage tank for said containers. The present invention also concerns a method for the use of such a silo. Background of the invention

Light empty containers, which are generally made of blown plastic, when supplied in bulk from the bottom outlet of a tank, behave as a material that can flow by gravity but highly prone to form "vaults" or "bridges" that they can interrupt the regular and continued flow of such articles. This is due to the fact that said packages frequently have irregular shapes, being provided with protuberances such as handles, necks, etc., which cause the packages to be interwoven with each other forming a kind of structure, usually called "vault" or "bridge", which , aided by the weight of the containers located at a higher level, it leans against the walls of the tank causing a blockage inside the silo, causing the containers involved in such a structure, as well as all those above them, to see each other. prevented from descending due to gravity towards the lower part of the silo.

Another limitation of empty light containers for storage in large silos lies in their relatively low resistance to crushing, either due to collisions caused by free fall from excessive height or the pressure exerted by the weight of a large number of containers piled above a particular container. This limits, therefore, the maximum height of free fall from the upper load inlet as well as the maximum height of stacking containers on a support surface, such as the bottom, within the silo. There are different devices in the state of the art aimed at alleviating the problem of the lack of fluidity in the bulk supply by gravity of materials constituted by irregularly shaped bodies, prone to form "vaults" or "bridges", which may be mentioned, by For example, patents US 2,905,365 and US 3,286,886 which describe different variants of bulk material supply devices, or hoppers, formed by a container of flat, rigid fixed walls, the cross section of whose tank is rectangular, decreasing from top to bottom, with an outlet opening arranged at the end lower. Attached by the inside of at least one of said walls, a flat, rigid plate is arranged, connected to means for transmitting a vibratory movement to said plate. With the vibration imparted by said plate directly on the materials stored in bulk the "vaults" or "bridges" are broken facilitating the creep of said materials by gravity. However, this vibration applied by said rigid plate directly on the materials stored in a hopper of similarly rigid walls is highly aggressive for the stored materials, so it is only applicable for bulk materials formed by solid, compact bodies, such as coal mineral or gravel, resulting entirely unsuitable for less resistant items, such as empty light containers.

In the PTC patent application ES 98/00229 of the present applicant, a silo for empty light containers is described whose walls are formed, at least in part, by sheets of a flexible material, such as a canvas, where some are provided means capable of transmitting to said flexible sheets a vibratory movement. This arrangement benefits from the advantages of the application of vibrations to break the "vaults" or "bridges" at the same time that such vibration is harmless to the containers. Also, in the PTC patent application ES 98/00230, also of the present applicant, a silo for storage of light hollow bodies is provided provided with a lower discharge opening comprising a dispensing device formed by plates, articulated with respect to opposite walls of the silo, inclined downward towards the center of the tank, so that the end of one of them, longer, extends partially below the end of the other. The inclination of said plates is adjustable in a dependent or independent manner, so that a discharge funnel with a slope slope and an opening can be obtained depending on the type of container to be stored. The longer plate has a wing near its free end that can be lifted to momentarily close the flow of containers without losing the slope and exit opening settings. In addition, said plates are provided with pushing means that allow shaking movement in order to facilitate the breakage of the "vaults" or "bridges" allowing the flow of light hollow bodies, such as empty plastic containers, stored . Although the two PCT patent applications cited above provide solutions for the problem of the difficulty of creep presented by bulk bodies prone to form "vaults" or "bridges", the problem of crushing risk remains unresolved. the containers due to the relatively low resistance of the empty light containers, either by receiving an excessive load or by falling from an excessive height.

In this sense, devices such as baffle plates, nets with sufficient passage openings for containers or labyrinths located at different levels within a high-rise silo are designed to limit the maximum height of free fall of a container on another container located at a lower level and the maximum height of stacking containers on a particular container. However, said baffle plates, nets or labyrinths are an impediment to the free flow of stored items that adds to the problem of the formation of "vaults" or "bridges."

Therefore, an objective of the present invention is to provide a silo for storage and regulated supply of empty light containers provided with means to prevent the formation of "vaults" or "bridges", or where appropriate to facilitate their breakage.

Another objective of the present invention is to provide a silo for storage and regulated supply of empty light containers provided with means to limit the maximum height of free fall of a container on another container located at a lower level and the maximum stacking height of containers on a particular container, inside the silo.

Finally, another objective of the present invention is to provide a method of storage and regulated supply of empty light packages by means of a silo provided with the means mentioned in the two preceding paragraphs. BRIEF EXPOSURE OF THE INVENTION These objectives are achieved in accordance with the present invention by providing a silo for storage and regulated supply of empty light packages of the type comprising a large tank provided with a cargo inlet at the top and a bottom with at least an adjustable discharge opening in its lower part, whose tank is filled and emptied by gravity. In order to limit the maximum height of free fall of a container on another container located at a lower level, as well as the maximum height of stacking containers on a particular container, said silo comprises a subdivision of said container into overlapping enclosures, filled by gravity, the height of which is a function of the type of container to be stored, said enclosures being delimited by lift planes retractable equipped with independent drive means, capable of moving them to open or close at least one passage through it to unload containers from an enclosure to the immediate lower enclosure.

In a preferred embodiment, said lift plane comprises at least one flexible sheet, such as a canvas, capable of being wound on a rotating core supported next to one of the side walls of said tank, a free front edge of said sheet being flexible fixed to a load bar capable of moving away from and approaching said rotating core moving, supported and guided, in a predetermined path formed, for example, by a pair of side rails on which corresponding wheels or skates fixed to both are supported ends of said loading bar. Said predetermined trajectory, which is preferably horizontal, comprises retractable stops that prevent the retraction of the loading bar in a situation of extension of the flexible sheet.

The loading bar is provided with pushing means comprising a pair of articulated arms, each of which is formed by two sections coupled to each other, each arm being articulated jointly at one end to the bench, in an area close to the rotating core, and at the other end to the loading bar, each of whose arms includes a tension spring fixed at one end of said sections and connected by a flexible element to the other of said sections so that it exerts on said stretches of a tendency to extend until they are aligned by pushing said load bar in the direction away from said rotating core. An electric motor acts on said rotating core for and against said pushing means to, respectively, extend and collect said flexible sheet.

In a more preferred embodiment, said lift plane comprises two of said flexible sheets, the corresponding rotating cores being supported in respective positions facing adjacent opposite side walls of said tank, with the corresponding predetermined paths arranged so that the respective Loading bars are mutually adjacent when said flexible sheets are fully extended. Being the trajectories of the ends of the horizontal load bars, the two flexible sheets, in an extended situation, are practically coplanar. However, an orientation of said flexible sheets slightly inclined towards the center of the lift plane appears equally flexible.

In another alternative embodiment, said lift plane comprises the less a flexible endless band extended between two rollers supported in respective positions facing adjacent side walls of said tank, and pressed by a pair of support rollers so that two superimposed sheets are very close together. Said endless flexible band comprises a portion with a wide and extensive opening, there being drive means connected to rotate, in a controlled manner, at least one of the rollers. The extension of said opening, in combination with said reciprocating movement makes said flexible band capable of adopting a position in which said opening is completely in the lower sheet, the upper sheet constituting said bearing plane, and at least another position (normally two, at opposite ends of the band) in which a part of said opening is in the upper sheet, superimposed on another part of said opening remaining in the lower sheet, facilitating a passage therethrough for the discharge of containers from an enclosure to the immediate lower enclosure. In this exemplary embodiment, two of said flexible endless bands would also preferably be mounted for each lift plane. The silo of the present invention optionally comprises side walls formed by flexible sheet canvases provided with reinforced peripheral edges, fixed to a support structure by means of tensioners distributed along said edges. As a function of reinforcing said side walls, extended cables are arranged crossing the outer face of said canvases, fixed by means of tensioners to said support structure.

In order to facilitate the manufacture, transport and assembly of said silo, taking into account its large dimensions, each of said lift planes is associated with a portion of the structure of said tank constituting a stackable modular assembly to form a tank, of a desired height, on a base module that includes said bottom and discharge opening, the modular assemblies being fixed to each other and with the base module in the final location by means of removable or permanent joints. The dispensing device described in the PTC patent application ES 98/00230 mentioned above is particularly suitable for constituting said bottom and discharge opening of said base module in the silo of the present invention. Regardless of the embodiment chosen for the lift planes, in the silo according to the present invention, means for detecting the level of accumulated packages on the lift plane and / or on the bottom are also provided. Control means are susceptible, depending on signals received from said detection means, of acting at least on said means of actuation of the lift planes to regulate the flow of the containers from one enclosure to the other and the maximum amounts thereof in each enclosure. Optionally, said control means are integrated in a general control that governs the feeding of said silo and the regulated supply of packages from it to, for example, a packaging line.

The operation of said silo is carried out following the method of storage and regulated supply of empty light packages described below, which is also an objective of the present invention.

With a silo like the one described above, the deposit of which is subdivided into superimposed enclosures by means of retractable lift planes, whose enclosures are filled superiorly by gravity, said lift planes being provided with independent means capable of selectively communicating with each other, in a desired moment, two of said enclosures, and the height of said enclosures being adequate to the minimum value of the maximum free fall height or the maximum stacking height capable of resisting a predetermined container type without deteriorating, said method is characterized in that: the feeding of said deposit is always initiated by loading the enclosure located at a higher level being the latter incommunicado with respect to the next; the discharge of any enclosure is always carried out by communicating it with the immediately inferior enclosure being empty, at least in part, and incommunicado with respect to the following, except when the immediately inferior enclosure is the enclosure located at the lowest level, which is delimited inferiorly by said bottom and said adjustable discharge opening, in which case, said discharge opening may be: closed, for storing containers; or open in a selected extension, for a regulated supply of said containers.

Brief description of the drawings

The invention will be better understood from the following detailed description of some preferred embodiments, the description of which is made with references to the attached drawings, in which: Fig. 1 is a vertical sectional view of a silo according to the invention, in the process of completing the complete filling with empty light containers for temporary storage, with the lower opening closed by means of a mobile wing; Fig. 2 is an exterior elevation view of a side wall of a part of the silo of the Fig. 1; Fig. 3 is a perspective view of an alternative embodiment of a lift plane for a silo like that of Fig. 1; Fig. 4 is a top view of a preferred embodiment of a silo lift plane of Fig. 1; Fig. 5 is a cross-section taken along the line VV of Fig. 4 in an enlarged detail; and Figs. 6 to 9 are schematic side views of the silo of Fig. 1 illustrating a possible filling / emptying sequence of said silo for a regulated supply of empty light packages.

Description of the preferred embodiments

Referring firstly to Fig. 1, a silo according to the present invention is seen comprising a large reservoir 1 provided with a loading inlet 2 at the top, a bottom 3 with at least one discharge opening 3 to adjustable in its lower part. A lifting device 30 for the upper loading of empty light containers A to said silo, and a conveyor belt 40, located immediately below the discharge opening 3 a for the collection and transport of the packages supplied by the silo towards, for example, a packaging line (not shown). The bottom 3 and the discharge opening shown in said Fig. 1, as well as in the

Figs. 6 to 9, correspond to the dispensing device described in the patent application PTC ES 98/00230 of the current applicant, mentioned above, which is particularly suitable for the silo of the present invention.

Said tank 1 comprises an internal subdivision in superimposed, gravity-filled enclosures B, the height H of whose enclosures B is a function of the type of container A to be stored, so that the maximum height of free fall and the maximum crushing pressure is limited supported by a container A located at a lower level. Said enclosures are delimited by retractable lift planes 4, equipped with independent drive means 5, 21, capable of moving them to open or close at least one passage through it for unloading A packages from an enclosure to the immediate enclosure. lower, except the enclosure located at the lowest level, which is delimited by the bottom 3 and discharge opening 3 a.

In Figs. 4 and 5 a preferred embodiment of a lift plane 4 is shown which is derived from an already classic system used in the awnings manufacturing sector, to which some simplifications and modifications have been practiced, whose implementation is very favorable in economic terms. In fact, said bearing plane 4 comprises two flexible sheets 6, of a material such as a canvas, capable of winding respectively on two rotating cores 7 supported in opposite positions next to opposite side walls of said tank 1. A free front edge of each flexible sheet 6 is fixed to a loading bar 8 capable of moving away from and approaching said rotating core 7 moving, supported and guided, in a predetermined path. Said supported and guided trajectory constitutes one of the specific contributions of this embodiment that differ from the classic application in the awnings sector, and is formed by a pair of lateral rails 9 on which corresponding li wheels or skates fixed to both ends of said loading bar 8. Preferably said rails 9 are horizontal, whereby both flexible sheets are, when extended, coplanar, with retractable stops 10 being provided in said predetermined path that prevent the retraction of the loading bar 8 in a situation of extension of the flexible sheet 6. For a better explanation of the operation, In Figs. 4 and 5 shows one of said flexible sheets 6 practically retracted (on the left) with its extended position indicated by dashed line, while the other flexible sheet 6 is shown fully extended (on the right). However, usually both flexible sheets 6 will extend or retract in unison.

The operation of said flexible sheets 6 is as follows. Pushing means drive said load bars 8 in the direction away from the respective rotating cores 7, that is, towards a central area of the lift plane 4. On the other hand, said drive means 5, which typically consist of a motor electric housed inside each rotating core 7, act in favor and against the corresponding thrust means to, respectively, extend and collect said flexible sheets 6.

Said pushing means comprise, for each flexible sheet 6, a pair of articulated arms 12, each of which is formed by two sections 12a, 12b articulated with each other, each arm 12 being articulated jointly at one end to the bench, in an area close to the rotating core 7, and at the other end to the loading bar 8, each of whose arms 12 includes a tension spring fixed at one end to one of said sections 12a, 12b and connected by a flexible element to the other of said sections 12a, 12b so that it exerts on said sections 12a, 12b a tendency to extend to remain aligned, while the drive means 5 act directly on said rotating core 7.

An alternative embodiment for said lift plane 4 is shown in Fig. 3, which comprises at least one endless flexible band 16 extended between two rollers 17 supported in respective opposite positions adjacent to opposite side walls of said tank 1 , and pressed by a pair of support rollers 20 so that there are two very close superimposed sheets, whose flexible band 16 comprises a portion with a wide and wide opening 18, there are drive means 21 connected to rotate at least one of the rollers 17 reciprocating so that said flexible band 16 is capable of adopting a position in which the entire opening 18 is in the lower sheet, the upper sheet constituting a support and closing plane of the upper enclosure, and at least one position wherein a part of said opening is in the top sheet, superimposed on another part of said opening 18 that is in the sheet infe rior, facilitating a passage through it for unloading containers A from an enclosure to the immediate lower enclosure (position illustrated in Fig. 3). This exemplary embodiment can also preferably be supplemented with two of said adjacent bands 16, arranged in a coplanar manner, for each lift plane 4.

In Fig. 2 one of the side walls walls of the silo is shown, formed by a canvas 13 of a sheet of a flexible material, fixed by tensioners 14, distributed along its reinforced peripheral edges 15, to a structure of support the. In order to reinforce said side walls, extended cables 22 are arranged crossing the outer face of said canvases 13, fixed by tensioners 23 to said support structure the.

According to a variant of the invention, the silo is also characterized in that each of the lift planes 4 described above is associated with a portion of the structure of said tank 1 (see again Fig. 1) constituting a modular assembly stackable to form a tank 1, of a desired height, on a base module that includes said bottom 3 and discharge opening 3 a, the modular assemblies being fixed to each other and with the base module in the final location by means of removable or permanent joints 19. The silo of the invention further comprises means for detecting the level of packages A accumulated on the lift plane 4 and / or on the bottom 3 and control means capable of acting at least on said actuating means 5, 21 of the lift planes 4 that divide said enclosures B based on signals received from said detection means. Said control means are integrated in a general control that governs the feeding of said silo and the regulated supply of packages A from it.

In Figs. 6 to 8 illustrates the method of storage and regulated supply of empty light A containers of the invention, using a silo as described in Figs. 1 to 5, whose method is characterized in that it acts by actuating the lift planes 4 so that in no case does a container A fall freely from a height greater than the height H of the enclosures, nor a container A supporting on top of he a height of piled containers greater than said height H of the enclosures. As stated above, the height H of said enclosures B has been defined to be adequate to the minimum value of the maximum free fall height or the maximum stacking height capable of withstanding a predetermined container type A without deterioration. An example of a logical sequence for filling and emptying said silo for a regulated supply of empty light containers A is as follows: a) the feeding of said tank 1 is initiated by loading the enclosure located at a higher level, being it incommunicado with respect to the following (Fig. 6); b) when the enclosure located at the highest level is full, or before, the flexible sheets 6 are operated to remove the lift plane 4 (Fig. 7) so that said enclosure located at the highest level communicates with the enclosure immediately lower, producing the discharge of the packages A; it is an indispensable condition, for the discharge of any enclosure, that the immediately inferior enclosure is empty, at least in part, and incommunicado with the following, except when the immediately inferior enclosure is the enclosure located at the lowest level; c) in case there are more than two superimposed B enclosures, the discharge of a particular enclosure on its enclosure immediately below can be carried out simultaneously with the loading or unloading of an enclosure located at a higher level (see Fig. 8) provided that meet the indispensable condition mentioned in paragraph b); d) this procedure is repeated sequentially downwards until the immediately lower enclosure is the enclosure located at the lowest level (Fig. 9), which is delimited inferiorly by said bottom 3 and said discharge opening 3 to adjustable, in which If there are two alternatives: if what is desired is to use the silo as a temporary storage warehouse A) said discharge opening 3a is closed (Fig. 1) allowing filling complete enclosure located at the lowest level; fl) then the flexible sheets 6 of the support plane 4 of the upper immediate enclosure are closed to proceed with their complete filling, and so on upwards until all the enclosures are filled (Fig. 1), or a number of desired enclosures; or if what is desired is to use the silo for a regulated supply of packages A e2) said discharge opening 3 a is open (Fig. 9) in a selected extension according to the required flow of packages; Y

£ 2) then steps a) -d) are repeated continuously with a suitable cadence to feed said required flow of containers through the discharge opening 3 a, whose cadence can be automatically controlled from signals coming from of means filling level sensors of each enclosure.

The examples of embodiment and use described above are intended to be merely illustrative and not limiting, and one skilled in the art may introduce numerous changes or modifications, both in the silo and in the method of use, without departing from the scope of the invention, which It is defined by the appended claims.

Claims

1.- Silo for storage and regulated supply of empty light containers, of the type comprising a large tank (1) provided with a loading inlet (2) at the top, a bottom (3) with at least one discharge opening (3a), adjustable, in its lower part and means inside to prevent deterioration in said containers (A) due to collisions by free fall from an excessive height and / or by a crushing caused by excessive stacking, characterized in that said means for preventing deterioration in the containers (A) comprise a subdivision of said tank (1) into overlapping enclosures (B), filled from above by gravity, the height (H) of whose enclosures (B) is a function of the type of container ( A) to be stored, so as to limit the maximum free fall height and the maximum crushing pressure supported by a container (A) at a lower level, said enclosures (B) being delimited by retractable lift planes (4) gifted d and independent drive means (5, 21), capable of moving them to open or close at least one passage through it for unloading containers (A) from an enclosure to the immediate lower enclosure, except the enclosure located at the highest level low, which is delimited by the bottom (3) and discharge opening (3a).

2. Silo, according to claim 1, characterized in that said support plane (4) comprises at least one flexible sheet (6), such as a canvas, capable of being wound on a rotating core (7) supported next to a from the side walls of said tank (1), a free front edge of said flexible sheet (6) being fixed to a loading bar (8) capable of moving away from and approaching said rotating core (7) moving, supported and guided , in a predetermined path.

3. Silo, according to claim 2, characterized in that it comprises retractable stops (10) in said predetermined path that prevent the retraction of the load bar (8) in the situation of extension of the flexible sheet (6).

4. Silo according to claim 3, characterized in that said lift plane (4) further comprises pushing means of said loading bar (8) in the direction away from the rotating core (7), said means of actuation acting drive (5), such as an electric motor coupled to said rotating core (7), for and against said thrust means for, respectively, extending and collecting said flexible sheet (6).

5. Silo, according to claim 3, characterized in that said lift plane (4) further comprises pushing means of said loading bar (8) in the direction of the rotating core (7), said actuating means acting ( 5) against already favor of said pushing means for, respectively, extending and collecting said flexible sheet (6).

6. Silo according to claim 4, characterized in that said pushing means comprise a pair of articulated arms (12), each of which is formed by two sections (12a, 12b) articulated with each other, each arm being (12) articulated jointly by one end to the bench, in an area close to the rotating core (7), and at the other end to the load bar (8), each of whose arms (12) includes a traction spring fixed at one end to one of said sections (12a, 12b) and connected by a flexible element to the other of said sections (12a, 12b) so that it exerts on said sections (12a, 12b) a tendency to extend until they are aligned.

7. Silo according to claim 2, characterized in that said predetermined path comprises a pair of directly opposite side rails (9) on which corresponding wheels (11) or skates fixed to both ends of said loading bar ( 8).

8. Silo, according to claim 7, characterized in that said rails (9) are horizontal.

9. Silo, according to any of claims 2 to 8, characterized in that said support plane (4) comprises two of said flexible sheets (6), the corresponding rotating cores (7) being supported in respective positions facing together opposite side walls of said reservoir (1), with corresponding predetermined paths arranged so that the respective loading bars (8) are mutually adjacent when said flexible sheets (6) are fully extended.

10. Silo according to claim 1, characterized in that said lift plane (4) comprises at least one endless flexible band (16) extended between two rollers (17) supported in respective opposite positions next to opposite side walls of said reservoir (1), and pressed by a pair of support rollers (20) so that there are two superimposed superimposed sheets, whose flexible band (16) comprises a portion with a wide and wide opening (18), there being drive means (21) connected to rotate at least one of the rollers (17) in a reciprocating manner such that said flexible band (16) is capable of adopting at least one position in which a part of said opening is in the sheet upper, superimposed on another part of said opening (18) remaining in the lower sheet, facilitating a passage therethrough for unloading containers (A) from an enclosure to the immediate lower enclosure.

11. Silo according to claim 1, characterized in that it comprises lateral walls formed by fixed sheet canvases (13), by means of tensioners (14) distributed along its reinforced peripheral edges (15), to a support structure (the).

12. Silo, according to claim 11, characterized in that it also comprises, depending on the reinforcement of the walls, cables (22) extended across the outer face of said canvases (13), fixed by means of tensioners (23) to said support structure (the).

13. Silo, according to claim 1, 11 or 12, characterized in that each of said lift planes (4) is associated with a portion of the structure of said tank (1) constituting a stackable modular assembly to form a tank (1), of a desired height, on a base module that includes said bottom (3) and discharge opening (3a), the modular assemblies being fixed to each other and with the base module in the final location by means of removable joints (19) or permanent

14. Silo according to claim 1, characterized in that it further comprises means for detecting the level of packages (A) accumulated on the lift plane (4) and / or on the bottom (3) and control means capable of acting at least on said actuation means (5, 21) of the lift planes (4) that divide said enclosures (B) according to signals received from said detection means.

15. Silo, according to claim 14, characterized in that said control means are integrated in a general control that governs the feeding of said silo and the regulated supply of containers (A) therefrom.

16.- Method of storage and regulated supply of empty light containers (A) by means of a silo of the type comprising a large tank (1) provided with a cargo inlet (2) at the top, and a bottom (3) with at least one discharge opening (3 a) adjustable in its lower part, said method being characterized in that said tank (1) is subdivided into enclosures (B) superimposed by retractable lift planes, whose enclosures (B) are filled superiorly by gravity, said lift planes being provided with independent means to selectively communicate with each other, at a desired time, two of said enclosures (B), the height (H) of said enclosures (B) being adequate to the minimum value of the maximum height of free fall or the maximum height of stacking capable of resisting a predetermined type of container (A) without deterioration, always feeding the said tank (1) by loading the site ado at a higher level, the latter being held incommunicado with respect to the next one and always carrying out the discharge of any enclosure communicating it with the immediately lower enclosure being empty, at least in part, and incommunicado with the next, except when the immediately inferior enclosure is the enclosure at the lowest level, which is delimited inferiorly by said bottom (3) and said adjustable discharge opening (3 a), in which case said discharge opening (3 a) can be closed, to store containers (A), or opened in a selected extension, for a regulated supply of said containers (A).