EP2429925A1

EP2429925A1 - Flexible container for packaging solid particulate materials in bulk, and use thereof

Info

Publication number: EP2429925A1
Application number: EP10728757A
Authority: EP
Inventors: Bernard Chartrel; Jean-Pierre Lecocq; Nicolas François CHEVALIER
Original assignee: Roquette Freres SA; Greif Flexibles France SARL
Current assignee: Roquette Freres SA; FPS Flexibles France SARL
Priority date: 2009-05-14
Filing date: 2010-05-12
Publication date: 2012-03-21
Also published as: FR2945525B1; US8590725B2; FR2945525A1; RU2011150819A; CN102438923A; RU2530838C2; WO2010130961A1; US20120055932A1

Abstract

The invention relates to a flexible container for packaging solid particulate materials in bulk, comprising a bottom (1), four substantially rectangular outer side walls (2) and a cap, characterized in that, inside the flexible container, a tube made of a flexible material and having a height lower than the height of the outer side walls is attached by vertical attachment lines (5) on the four outer side walls (2) of the vessel in order to define a central compartment (6) and four peripheral compartments separated from the central compartment by four inner walls (8a, 8b, 8c, 8d), respectively, each of the inner walls including a central pouring means (11) at the upper edge thereof.

Description

FLEXIBLE CONTAINER FOR THE PACKAGING OF PARTICULATE SOLID BULK MATERIALS AND USE THEREOF

The present invention relates to a novel flexible container for packaging bulk particulate solids and a method of filling such a container.

Flexible large containers for the packaging of large quantities of particulate solids, also known as FIBC (Flexible Bulk Container) or FIBC (Flexible Intermediate BuIk Container) bags or "Big Bag", are known for many years and used for the protection, storage and transport of bulk particulate matter such as food materials (sugar, flour, starch), polymer granules or chemicals.

These containers are conventionally made of polymer fiber fabric (for example PP, HDPE, LLDPE), optionally sealed by coating.

The capacity of these containers is generally between 0.5 and 2 m ³ . The large size and mass of containers, once filled, make their handling difficult and in some cases dangerous. Indeed, when, in order to optimize the use of the storage space, it is decided to stack the bags filled on several levels, it is essential to ensure the perfect stability of the stacks, because an imbalance can quickly lead to slips and falls with harmful consequences.

Moreover, despite their rectangular bottom that would normally allow almost complete filling of the available transport and storage surface, the significant pressure that bulk materials exert on the flexible sidewalls of containers makes their actual form deviate substantially from their parallelepipic ideal shape. Thus, in a truck with a floor area of 32 m ² , it is impossible to juxtapose more than 24 filled containers, each of a square base Im x Im.

The Applicants have also found that, despite the heavy weight of the filled containers, it could happen that during transport in trucks, a small number of bags are reversed, making it very difficult, if not impossible, unloading them by forklifts .

It is furthermore common practice to subject the container, during its filling, to vibrations intended to obtain optimal packing of the bulk materials. Filling apparatus for delivering such vibrations are heavy, complex and expensive. In such an apparatus, the container is raised above the ground due to the presence of the vibrator at the base of the apparatus. Therefore, any human intervention during the filling process, for example during the introduction or removal of the filling device or in the event of a malfunction, is done at a distance from the ground which presents any evidence of the risk of falling. In the context of their research aimed at optimizing the packaging of bulk particulate matter in "Big Bag" type flexible containers, the Applicants have discovered a relatively simple means of overcoming all the disadvantages listed above. Indeed, the Applicants have found that the creation, within the volume of the flexible container, a set of compartments in communication with each other, allowed surprisingly, to obtain filled bags whose shape is closer to that of a rectangular parallelepiped than that of the known containers. The shape less rounded filled containers of the present invention allowed to store and transport a larger number in a given space. In a surface truck of 32 m ² it was thus possible to juxtapose 26 containers instead of 24. The bags according to the invention also had the advantage of being much more stable than the known bags without inner walls, and were never knocked over during transport in trucks.

Another advantage of the containers of the present invention lies in the possibility of filling them satisfactorily, in the absence of any vibration system. This allows, throughout the filling process, to put them on the floor or simply on pallets, and any human intervention at the cap of the container then presents no risk of falling. It goes without saying that the bag filling system of the present invention can be designed, in the absence of a vibrator, much more simply. The very great stability of the containers of the present invention also makes it possible to stack them on three levels, which represents a considerable saving of space in comparison with the known bags which, for the security reasons mentioned above, could only be stacked on two levels.

Finally, it is common practice to let the containers rest, after filling, for a time, of the order of a few hours, to let out air before handling the filled bag. Thanks to the containers and the process of the invention this rest time, previously necessary for the settlement of the particulate matter, is superfluous and it becomes possible to work in a just-in-time flow.

Flexible containers were already known for packing bulk particulates with inserts. Thus, US Pat. No. 6,900,975 discloses FIBC type bags comprising inserts made of antistatic fiber ribbons. These ribbons, however, do not form real internal walls as described below, capable of imposing a filling order of the various internal compartments of the bags. When particulate matter is poured from the top into a container as described in US 6,900,975, it uniformly fills the entire extent of the base of the bag and is not first retained in the central compartment and then spilled, overflow, in the other compartments as in the present invention.

The flexible containers described in these documents therefore do not make it possible to obtain bags, filled with bulk particulate matter, having a stability equivalent to that of the bags of the present invention.

It is important to note that the benefits described above can be achieved through a new simple and inexpensive container design. The containers of the present invention are distinguished from known containers by the fact that a single tube of flexible material is fixed by vertical attachment lines on each of the four side walls of the container, thus defining a central compartment and four angular compartments. , or devices. The present invention therefore relates to a flexible container for the packaging of bulk particulate solids, comprising a bottom, four substantially rectangular outer side walls and a cap, characterized in that within the flexible container a tube of a flexible material, having a height less than the height of the outer side walls, is fixed by vertical attachment lines on the four outer side walls of the container so as to define a central compartment, open upwards and downwards, and four peripheral compartments separated from the central compartment by four internal walls, each of the inner walls having, at its upper edge, a central discharge means.

The tube of flexible material, also called skirt, can be characterized by its length and its perimeter. It will be readily understood that after fixing the tube on the outer side walls of the container, the length of the tube corresponds to the height h of each of the inner walls and the perimeter of the tube to the sum of the widths of the four internal walls.

As indicated above, the height h of each of the inner walls is less than the height H of the outer side walls of the container. Preferably, the ratio of the height h of the four internal walls to the height H of the external lateral walls is between 0.65 and 0.9, preferably between 0.7 and 0.85.

The inner walls formed by fixing the tube on the outer side walls are preferably not in contact with the bottom of the container but their lower edge, preferably substantially horizontal, is located at a distance Dl from the bottom of the flexible container. This puts the central compartment in communication with each of the four peripheral compartments. When filling the container, the particulate material, introduced into the central compartment from above, can thus spread over the entire base of the container to a certain height which is limited by the distance Dl. This initial filling of the entire base of the container is essential for the satisfactory operation of the process because it ensures the stability of the bag during the filling of the central compartment. Said distance D1 is preferably between 4 and 12%, in particular between 5 and 10% of the total height H of the external lateral walls of the container. In other words, for a container 150 cm high, the lower edge of the walls internals is preferably at a distance of between 6 and 18 cm.

Similarly, the upper edge, substantially horizontal, of the four inner walls is not at the upper edge of the container but is located at a certain vertical distance D2 thereof. This distance D2 is preferably between 5 and 20%, in particular between 10 and 15% of the total height H of the external lateral walls of the container. In other words, for a container with a height of 150 cm, the upper edge of the inner walls is located at a vertical distance D2 between 7.5 and 30 cm.

Each of the inner walls has in the center of its upper edge spill means that can channel or centralize the overflow or flow of particulate matter when the central compartment is almost filled. This discharge means can in principle have any shape, as long as it allows to direct the flow of particulate matter, overflowing the central compartment, to each of the peripheral compartments. Examples of spill means include a central slot or a central notch. The position, the size and the depth of the discharge means are advantageously chosen so that the flow of the particulate matter from the central compartment to the peripheral compartments, during the filling of the peripheral compartments, is done solely via these means of spill. In other words, it seems important to avoid that the flow of particulate material entering the container overflows uncontrollably over the entire extent of the upper edges of the side walls.

The dimensions of the discharge means thus depend, of course, on the filling speed of the containers and those skilled in the art will know how to adjust them according to the latter. Generally, when the pouring means is a notch or a simple slot made in the center of the upper edge of each of the inner walls, the depth P thereof is preferably between 5 and 15% of the height h of each of the inner walls.

Thanks to their particular internal structure, the filling of the flexible containers of the present invention is essentially divided into four phases: a first filling phase of the base of the bag essentially over the entire extent thereof, a second filling phase of the central compartment during which the filling of the peripheral compartments, defined by the side walls, is non-existent or negligible, - a third phase of filling the peripheral compartments by spilling the particulate matter from the central compartment via the discharge means; this phase begins towards the end of the filling phase of the central compartment as soon as the level of the particulate material arrives at the level of the discharge means, a fourth optional phase of filling of the upper part of the bag, beyond the edge upper internal walls. It will be readily understood that, in order for the filling of the flexible container to proceed in this manner, the side walls must be designed to retain the particulate matter in the central compartment during the second phase. In other words, the inner walls are preferably solid walls, devoid of orifices or slits other than the central slot at the upper edge. One could certainly consider the presence of orifices of small or very small size, linked for example to the textile structure of the material forming the side walls, but the runoff of the particulate matter by these small orifices shall be negligible in relation to the filling that takes place during the third phase via the discharge means.

The flexible material tube is attached to the four outer side walls of the container by substantially vertical fastening lines. These attachment lines are advantageously seam lines or weld lines, preferably seam lines. The tube may be fixed by one or, for reasons of strength, by several parallel attachment lines on each of the outer side walls. When the fastening is done by several parallel lines, all are preferably located in the central vertical zone of the side wall, in particular in the vertical zone of said wall covering less than 20%, preferably less than 15% of the width of the wall. the side wall.

The perimeter of the tube of flexible material fixed on the side walls of course depends on the total perimeter of the cross section of the container. It must both be inferior to the latter and have sufficient value so that the tube does not exert excessive traction on the side walls when the bag is filled. It can be calculated that the ratio of the perimeter of the cross-section of the flexible bag (= 4 × width of the outer side walls) to the perimeter of the cross-section of the tube (= perimeter of the central compartment) is preferably between 1.27 and 1 , 41, these two values respectively corresponding to a circular central compartment and a central square compartment.

The cap of the flexible container of the present invention can in principle have any shape known or still unknown in the art provided that it does not alter the intrinsic qualities of the present invention. The invention is concerned above all with the vertical parts (external sidewalls and walls internal) and not on the horizontal parts (bottom and cap) of the container.

In a particular embodiment, the container cap has a hopper shape with a central filling port and, similarly, the bottom of the flexible container has a hopper shape with a central drain port. The filling and emptying holes may be closed by any appropriate closing means. Filling and emptying chutes are preferably provided respectively in the bonnet and the bottom of the bags. These troughs are preferably equipped externally with ligation links fixed by stitching in the assembly of the fabric elements. Closing is done by knotting the links, usually on a folding goose-shaped troughs.

The present invention further relates to a method of packaging bulk particulate solids using the flexible container as described above. This method comprises pouring the bulk particulate solid material to be packaged from the top of the flexible container into the central compartment thereof, the particulate solid material first filling the base of the bag, then the central compartment and then overflow. , the four peripheral compartments of the container. The four distinct phases of the process according to the invention have been described above.

As explained in the introduction, the flexible containers of the present invention, once filled, exhibit excellent stability, even when they have not been subjected to vibration during their filling. Therefore, in a preferred embodiment of the process of the invention, the flexible container is not subjected, during its filling, to vibrations intended to increase the degree of compaction of the bulk particulate solid material. The Applicants have found that it is advantageous not to completely fill the flexible containers according to the invention. It is advisable to stop spilling of the particulate solid material through the filling port when the volume filling ratio of the flexible container is between 90 and 99%, preferably between 92 and 95%, of the complete filling. This stop before filling the bag completely prevents the filling of the filling pipe of the station which would distort the weight of the product.

The present invention is now explained in detail with reference to the accompanying figures, in which, Figure 1 is a perspective view of a container according to the invention, Figure 2 shows a cross section of a container according to the invention. at about mid-height, and Figure 3 is a detail view of the upper edge of an inner wall showing two different embodiments of the discharge means.

FIG. 1 illustrates a flexible container according to the invention comprising a bottom 1 and four external lateral walls 2 of height H. In this figure, the cap has been omitted for simplification purposes. Within the volume defined by the bottom 1 and the four side walls 2, a tube of flexible material is fixed by four vertical attachment lines 5 respectively on the four outer side walls 2. Each of the vertical attachment lines 5 is substantially in the center of each of the outer side walls 2. Between two vertical fastening lines 5 on two adjacent external side walls are thus defined four internal walls 8a, 8b, 8c, 8d of height h (less than the height H of the external side walls 2 ). The four inner walls define, on the one hand, a central compartment open up and down and, on the other hand, on the other hand, four peripheral compartments also open upwards and downwards. The central compartment is thus in fluid communication with the peripheral compartments. The lower end of each vertical attachment line 5 is at a distance D1 from the bottom 1 of the container and the upper end of each vertical attachment line 5 is at a distance D2 from the upper edge of the container. Each of the inner walls 8a-8d has, at its upper edge, a notch 11b.

Figure 2 shows the cross-section of the container of Figure 1 at about mid-height thereof. The four inner walls 8a, 8b, 8c, 8d, fixed on the external lateral walls 2 by fastening lines 5, define a central compartment 6 of square shape and four peripheral compartments 7a, 7b, 7c, 7d, identical of triangular section. .

Figure 3 shows two embodiments of the discharge means, namely (a) a slot 11a of depth P in the center of the upper edge of the inner wall, and

(b) a notch 11b rounded in depth P in the center of the upper edge of the inner wall.

Claims

A flexible container for packaging bulk particulate solids comprising a bottom (1), four essentially rectangular outer side walls (2) and a cap (3), characterized in that inside the flexible container a tube of flexible material having a height less than the height of the outer side walls is fixed by vertical fastening lines (5) on the four outer side walls (2) of the container so as to define a central compartment ( 6) and four peripheral compartments (7a, 7b, 7c, 7d) separated from the central compartment respectively by four inner walls (8a, 8b, 8c, 8d), each of the inner walls having, at its upper edge, a means of central spill (11).

2. Flexible container according to claim 1, characterized in that the ratio of the height (h) of the four inner walls (8a, 8b, 8c, 8d) to the height (H) of the outer side walls (2) is included between 0.65 and 0.9, preferably between 0.7 and 0.85.

3. flexible container according to claim 1 or 2, characterized in that the lower edge (9) substantially horizontal of the four inner walls (8a, 8b, 8c, 8d) is located at a distance (Dl) from the bottom of the container flexible thus establishing a communication between the central compartment (6) and each of the four peripheral compartments (7a, 7b, 7c, 7d), said distance (Dl) being between 4 and 12%, preferably between 5 and 10% of the total height (H) of the outer side walls of the container.

4. flexible container according to any one of the preceding claims, characterized in that the upper edge (10) substantially horizontal of the four internal walls (8a, 8b, 8c, 8d) is located at a distance (D2) from the upper edge of the flexible container, said distance (D2) being between 5 and 20%, preferably between 10 and 15% of the height; total (H) external side walls of the container.

5. Flexible container according to any one of the preceding claims, characterized in that the discharge means is a central slot (11a) or a central notch (11b).

6. Flexible container according to any one of the preceding claims, characterized in that the depth (P) of the central slot (11a) or the central notch (Hb) is between 5 and 15% of the height ( h) each of the internal walls.

7. Flexible container according to any one of the preceding claims, characterized in that the inner walls (8a, 8b, 8c, 8d) are solid walls without holes.

8. Flexible container according to any one of the preceding claims, characterized in that the ratio of the perimeter of the cross section of the flexible bag (= 4 x width of the outer side walls) to the perimeter of the cross section of the tube (4) (= perimeter of the central compartment) is between 1.27 and 1.41.

9. Flexible container according to any one of the preceding claims, characterized in that the vertical fastening lines (5) are seam lines or welding, preferably seam lines.

10. Flexible container according to any one of the preceding claims, characterized in that the cap (3) of the flexible container has a hopper shape with a central filling opening.

Flexible container according to one of the preceding claims, characterized in that the bottom (1) of the flexible container has a hopper shape with a central drain hole.

A method of packaging bulk particulate solids comprising spilling a bulk particulate solid material from above into the central compartment (6) of a flexible container according to any one of the preceding claims, the particulate solid material. first filling said central compartment (6) and then, by overflow, the four peripheral compartments (7a, 7b, 7c, 7d) of said flexible container.

13. A method of packaging according to claim 12, characterized in that the flexible container is not subjected to vibrations intended to increase the degree of compaction of the particulate solid material in bulk.

14. The method of packaging according to claim 13, characterized in that the spill of the particulate solid material is stopped when the volume filling ratio of the flexible container is between 90 and 99%, preferably between 92 and 95%. .