EP0571516B1

EP0571516B1 - Block-shaped container for bulk material

Info

Publication number: EP0571516B1
Application number: EP92906570A
Authority: EP
Inventors: Jacques Pierre Henri Basconnet
Original assignee: Koninklijke Emballage Industrie Van Leer BV
Current assignee: EMPAC BETEILIGUNGS-GMBH
Priority date: 1991-02-22
Filing date: 1992-02-24
Publication date: 1994-12-14
Anticipated expiration: 2012-02-24
Also published as: DE69200920T2; DE69200920D1; EP0571516A1; NL9100318A; WO1992014660A1

Abstract

A block-shaped container (1) for bulk material, which container (1) is made of flexible material and has stabilisation means (5) for preventing its sidewalls (12, 13) from bulging out under the influence of the bulk material. These stabilisation means (5) are provided in the form of strips of flexible material (7) which are fixed at one side to a sidewall of the container (12, 13) and at the other side to a thin-walled core (16) with a cross section which is closed in a plane at right angles to the sidewalls (12, 13). The core (6) is preferably a ring or pipe of flexible material, on the outside of which the strips (7) of flexible material run. The filling opening is situated directly above the core (6), in such a way that when the container (1) is being filled the bulk material initially collects in the core (6) and said bulk material presses the flexible material of the core (6) radially outwards and pulls it taut to a cylindrical shape. The stable core (6) thus formed, by way of the flexible strips (7), prevents the container walls from bulging out.

Description

The invention relates to a block-shaped container for bulk material, said container being made of a flexible sheet material and having on the inside stabilisation means fixed to the side walls for preventing its side walls from bulging out under the influence of the bulk material, and also having a filling opening situated on its top side, the stabilisation means containing strips of flexible material which are fixed at one side to a side wall and at the other side to a thin-walled tubular core which is generally parallel with respect to the side walls.
Such a container is known from GB-A-1544631. Although this known container is suitable for bulk material, it has the disadvantage that the tightness, in particular with respect to liquid or dust, cannot easily be guaranteed. The outer walls of the container are selected primarily on the basis of their load-carrying capacity, which means that they consist of materials which do not necessarily have the required tightness. Moreover, the provision of separate liners having the required tightness which fit in between the stabilisation means inside the container appears to be cumbersome.
The object of the invention is therefore to provide a container of the above type which hat the required tightness. This object is achieved in that a lining is provided, said lining having a slit or cut at the level of each strip, each strip projecting outwards relative to the lining through the slit or cut, and the lining edges situated on either side of the strip being adhesively fastened to the strip in a tight manner by means of an essentially L-shaped tape.
In this case an L-shaped adhesive tape is preferably fixed at one side to the outwardly projecting edge of the strip and at the other side to the outside of the corresponding lining edge. In order to reinforce the container, a cord can be provided in a packet comprising a first adhesive tape, a first side wall half, a strip, a second side wall half, and a second adhesive tape.
The core can be a ring or pipe of flexible material, on the outside of which the strips of flexible material run. The whole container, including the stabilisation means, can thus be folded up to a small packet, so that transportation to the falling place is facilitated.
The stabilisation means support the side walls, preferably halfway between the vertical edges of the side walls. In this way it can be ensured that the bulging out of said side walls remains limited.
Through the strips of flexible material and the thin-walled core, the interior space of the container is divided into five parts. In order to ensure that bridging cannot occur in any of these parts during filling or emptying of the container, these five regions have approximately the same surfaces. Each of the surfaces has a size which is large enough to avoid bridging in the bulk material.
In this respect a further improvement can be obtained if the strips and the core are of equal length in the vertical direction and do not extend to the top edge and the bottom edge of the side walls. The five regions into which the inside of the container is divided are thus connected, in such a way that the container can be filled and also emptied completely through one filling and emptying opening.
During filling of the container the best results are obtained if the filling opening is situated directly above the core, in such a way that the bulk material initially collects in the core, said bulk material pressing the flexible material of the core radially outwards and pulling it taut to a cylindrical shape. As soon as the core is filled, it forms a stable cylinder, under the influence of the radially outward directed pressure force of the bulk material. The material put in then runs over the edge of the core into the areas lying outside and bounded by the strips of flexible material.
The bulk material come into contact with the walls of the container and, through the fact that the horizontal length of the strips is approximately the same as the distance of the cylindrical wall filled with the bulk material from the side walls of the container, the block shape of the container can still be retained, despite the outwardly directed bulk material load exerted on the side walls.
Different methods can be used for filling of the container. First of all, the container can be opened out by directing a jet of air onto the filling opening. The core of flexible material is thus blown open in such a way that it is ensured that the bulk material initially collects in said core.
According to another known filling method, the container is suspended by suspension lugs near its top corners. The container is thus opened, but it is not yet ensured that the core is opened in a suitable way to take the bulk material. In that case the side walls, near each top corner where the suspension lugs are provided, and the core are fixed to each other by means of pull tapes or cords, in such a way that when the container is suspended the core is held open by said pull tapes or cords. Here again, the bulk material will thus initially collect in the core during filling.
As regards the manufacturing of the container, it is advantageous if the side walls each comprise two halves connected to each other by a seam, in which seam a strip is also fixed. The halves of two adjacent side walls can also be integral. In this embodiment only four seams are present in the side walls, which constitutes a major advantage for the production of the container.
For containers which have to be dustproof, the seams can be made in such a way that the vertical edges of two wall halves belonging together in each case first run outwards, enclosing the vertical edge of the corresponding strip, then run folded away from each other through 180° back to the outside of the side wall and, finally, run folded away from each other through 90°, while a cord is sewn into the seam parts running outwards relative to the side wall. This special form of seam ensures that virtually no dust can escape from the inside of the container to the outside. Moreover, these seams can be produced simply with a standard sewing machine.
The invention will be explained in greater detail below with reference to an example of an embodiment shown in the figures.
Figure 1 shows a container in perspective, in which the top side is partially left out.
Figure 2 shows a side view of the container, in which a side wall is partially left out.
Figure 3 shows a detail of the seam of the container.
Figures 4a to 4d show the various stages of filling of the container.
Figure 5 shows a first phase of the production of the stabilisation means according to the invention.
Figure 6 shows a second phase.
Figure 7 shows the finished stabilisation means.
Figure 8 shows the side walls of the container for fixing together.
Figure 9 shows a cut-away view in perspective of a container with liquid-tight lining.
Figure 10 shows a detail of Figure 9.
The container shown in Figure 1 comprises side walls 1 to 4, and also interior stabilisation means 5. As can also be seen in Figure 2, these stabilisation means 5 have a core 6 of supple material and four flexible edge strips 7. These edge strips 7 are fixed at one side to the core 6 and at the other side to one of the walls 1 to 4 in each case. The container is also provided with a top face 8 and a bottom face 9, each provided with a filling opening 10 and an emptying opening 11 respectively.
The supple strips 7 are fixed in the centre of the side walls 1 to 4, in the manner shown in Figure 3. As in Figure 1, it can be seen clearly here that the side walls, for example side wall 1, are made up of two halves 12, 13, which together with the supple strips 7 are sewn together. The adjacent edges of the wall halves 12, 13 are, as shown, bent away from each other through 180°, and then bent away in the opposite direction through 90°, in such a way that strips of material between which the flexible strips 7 can be sewn are obtained. Such a seam is highly dustproof. Owing to its ready accessibility, it can be easily made on a standard sewing machine.
As can also be seen clearly in Figure 1, the wall halves 12, 13 run through into the wall halves of the adjoining side wall, as a result of which a sturdy construction is obtained.
Fitted near the corners of the container are suspension lugs 14, by means of which the container can be suspended on a filling or unloading unit. Cords or tapes 15 which are fixed to the core 6 can also be provided near the corners. As soon as the container is opened out and suspended by its suspension lugs 14, the core 6 can also be opened out by means of the cords or tapes 15. Such cords or tapes 15 can be dispensed with if the container is opened out by means of a blowing device.
In Figures 4a to 4d the container is shown, partially cut away, during various stages of filling with a granular material. As shown in Figure 4a, the core is opened out, either by the blowing open of the container or by means of the cords or tapes 15, not shown here. A certain quantity of material initially collects on the bottom of the container, in such a way that the bottom edge of the core 6 is reached in the end. The core is then filled internally (see Fig. 4b). Following that, the situation shown in Figure 4c is reached, in which situation the core 6 is filled completely and the material goes into the space determined by the supple strips 7 and the core 6. Only now does the material come to rest against the outer walls 4 of the container but, since they can be retained by the strips of supple material and the core 6 stabilised by the bulk material, they cannot bulge outwards. The container is shown completely filled in Figure 4d.
It will be clear that during emptying of the container the part of the container directly below the core 6 runs empty first, and then the adjoining spaces.
Figures 5 to 8 show different stages in the production of stabilisation means and the container walls. As shown in Figure 5, a self-contained length of supple material is first of all folded in such a way that a bottom wall 16, a top wall 17 and two folded walls 18, 19 are obtained. These walls are connected to each other by the fold edges 20 and 21. Figure 6 shows that the walls are then fixed to each other by means of the weld seams 22, as a result of which the four flexible edge strips 7 and the core 6 of supple material are obtained. Figure 7 shows all this again when opened out.
The side walls of the container are then assembled from strips of supple material each comprising a half 12, 13 of a side wall.
These halves are sewn together by edge strips 23, a supple strip 7 of the stabilisation means in each case being sewn securely between two adjoining wall strips (see also Figure 3).
As mentioned, the height of the edge strips 7 and the core 6 is less than the height of the wall halves 12, 13, in such a way that the stabilisation means do not run through to the top wall and bottom wall of the container then to be fitted. This top wall and this bottom wall are then also fastened together by means of the dustproof seams shown in Figure 3, the difference being that the supple strips 7 are left out.
In the container shown in Figure 9 a lining of liquid-tight material such as polyethylene, indicated in its entirety by 24, is fitted. The container has the side wall halves 12, 13 with edge strips 23, already described above. A top wall 25 and bottom wall 26 are also shown, also with edge strips 27.
The lining 24 has a slit 29 in each of its side walls 28. The outer edge 30 of a strip 7 projects through said slit in each case. Strips 7 and core 6 are not visible.
As can be seen in Figure 10, the edge 30 of each strip 7 is fixed by means of a double L-shaped adhesive tape 31 in a liquid-tight manner to the lining edges adjoining the slit 29. Finally, a cord 36 is sewn through the packet comprising the strip 7 and lining 24 and adhesive tape 31, fixed to each other in this way in a liquid-tight manner, on the one hand, and the side wall halves 12, 13, on the other.
It is also pointed out that openings 32, 33 are provided in the top wall 26 and in the bottom wall 25, through which filling and emptying channels 34 and 35 respectively project when the container is assembled. These channels 34, 35 are joined together in the known way to shut off the lining.
In the embodiment shown, the adhesive tape 31 is double L-shaped and is folded around the edge 30 of strip 7. In that case cord 36 is also sewn through the adhesive tape halves 31.
According to a variant, two L-shaped, loose adhesive tapes can be used. The cord in this case need only be sewn through the side wall halves and the strip 7.

Claims

Block-shaped container for bulk material, said container being made of a flexible sheet material and having on the inside stabilisation means (5) fixed to the side walls (1-4) for preventing its side walls (1-4) from bulging out under the influence of the bulk material, and also having a filling opening (10) situated on its top side, the stabilisation means (5) containing strips (7) of flexible material which are fixed at one side to a side wall (1-4) and at the other side to a thin-walled tubular core (6) which is generally parallel with respect to the side walls (1-4), characterised in that a lining (24) is provided, said lining (24) having a slit or cut (29) at the level of each strip (7), each strip (7) projecting outwards relative to the lining (24) through the slit or cut (29), and the lining edges situated on either side of the strip (7) being adhesively fastened to the strip (7) in a tight manner by means of an essentially L-shaped tape (31).
Container according to claim 1, in which an L-shaped tape (31) is fixed at one side to the outwardly projecting edge (30) of the strip (7) and at the other side to the outside of the corresponding lining edge.
Container according to Claim 2, in which a cord (36) is sewn into a layered structure comprising a first of said L-shaped tapes (31), a first side wall half (12, 13), a strip (7), a second side wall half (12, 13), and a second of said L-shaped tapes (31).
Container according to Claim 2, in which a cord (36) is sewn into a layered structure comprising a first side wall half (12, 13), a strip (7) and a second side wall half (12, 13).
Container according to Claim 1, 2, 3 or 4, in which the core (6) is a ring or pipe of flexible material, on the outside of which the strips (7) of flexible material run.
Container according to Claim 5, in which the internal space of the container is divided into five regions with approximately the same surface areas by the core (6) and the strips (7).
Container according to Claim 5 or 6, in which the strips (7) and the core (6) are of the same length in the vertical direction, and do not extend to the top edge and the bottom edge of the side walls (1-4).
Container according to Claim 5, 6 or 7, in which the filling opening (10) is situated immediately above the core (6), in such a way that when the container is filled, the bulk material initially collects in the core (6), said bulk material pressing the flexible material of the core (6) radially outwards and pulling it taut to a cylindrical shape.
Container according to Claim 8, in which the dimension of the strips (7) in the direction perpendicular with respect to the corresponding side walls (1-4) is approximately the same as the distance between the cylindrical wall filled with bulk material and the side walls (1-4) of the container.
Container according to any of the preceding claims, in which the side walls (1-4) are provided with suspension lugs (14) near each top corner of the container, and the core (6) is fixed to the side walls (1-4) near the suspension lugs (14) by means of pull tapes or cords (15), in such a way that when the container is suspended the core (6) is held open by said pull tapes or cords (15).
Container according to any of the preceding claims, in which the side walls (1-4) each comprise two halves (12, 13) connected to each other by a seam, in which seam a strip (7) is also fixed.
Container according to any of the preceeding claims, in which the halves (12, 13) of every two adjacent side walls (1-4) form a whole.
Container according to Claim 12, in which the vertical edges of two adjacent wall halves (12, 13) first run outwards, enclosing the vertical edge (30) of the corresponding strip (7), then run folded away from each other through 180° back to the outside of the side wall and, finally, run folded away from each other through 90°, while a cord (36) is sewn into the seam parts running outwards relative to the side wall (1-4).
Container according to any of the preceding claims, in which the strips (7) and the core (6) are made of a length of flexible material, which length being formed into a square having four walls (16-19), of which two walls (16, 19) are then folded inwards over their respective lines (21) lying midway between the wall corner edges (20), in such a way that the two middle lines (21) concerned come to lie near each other, and a layered structure is obtained comprising in succession: an unfolded wall portion (17), two inwardly folded halves of an adjacent wall portion (16, 19) and, finally, an unfolded wall portion (16), after which the unfolded wall portions (16, 17) are fastened at a distance from their corner edge (20) according to a line (22), parallel to a corner edge (20), to the adjacent half of an inwardly folded wall portion (18,19) in such a way that a strip (7) is formed between each corner edge (20) and a fastening line (22), and the wall portions lying between the fastening lines (22) form the core (7).