WO2007031330A1

WO2007031330A1 - Method and a machine for the process manufacturing of erect flexible containers and for the subsequent filling and closure thereof

Info

Publication number: WO2007031330A1
Application number: PCT/EP2006/009005
Authority: WO
Inventors: Ramon Figols Gamiz
Original assignee: Volpak, S.A.
Priority date: 2005-09-16
Filing date: 2006-09-15
Publication date: 2007-03-22
Also published as: ES2292311A1; ES2292311B1

Abstract

Method for the manufacturing of erect flexible containers starting from a flat, heat-sealable sheet, which comprises, amongst others, the following stages: folding the sheet in a triple fold, to define two side walls with a different height and a lower transverse wall; folding one side towards the other, to make an upper downward fold and an upper upward fold, with the edges of both sides remaining flush; joining by welding lateral portions with the lower and upper transverse walls, as well as said lateral portions, in respective vertical welding strips, to form a receptacle equipped with a provisional upper mouth; cutting free upper portions of both lateral portions, to form a mouth neck; cutting the sheet through the vertical welding strips, to separate the receptacle from the sheet; filling the container by introducing the product to be stored through said provisional mouth; and joining by welding the perimeter edges of the mouth neck.

Description

D E S C R I P T I O N

Method and a machine for the process manufacturing of erect flexible containers and for the subsequent filling and closure thereof

Technical field of the invention

The invention relates to a method and a machine for the process manufacturing of containers, starting from a heat-sealable sheet, and for the subsequent filling and closure thereof. The containers are specifically designed to contain liquid products and to remain erect, in a vertical position, when they are full. Background of the invention

Currently, containers manufactured from a flexible, weldable sheet are known that are capable of remaining in an erect position once filled. One type of known container is that which comprises two opposite side walls, joined by welding along their lateral edges and continuously joined to a back wall that is folded inward, forming a watertight receptacle. In general, weldings are performed along the junction lines between the back wall and the side walls, as well as between facing portions of said back and side walls to configure a deformable back wall in the form of an inverted dome when the container is full, which does not protrude from the essentially elliptical perimeter, formed by the junction lines between said back wall and the corresponding side walls, which serves as a support whereon the full container stands in an erect position.

This type of containers further comprise a ceiling wall that is folded inward and joined to the side walls in a manner analogous to that of the back wall and the sides of the container to configure a deformable ceiling wall in the shape of a dome when the container is full.

There are different solutions to equip the container with adequate mouths in those cases wherein the containers are designed to store liquid products. In these cases, the mouths designed to pour the liquids must be equipped with the end of a corresponding mouth neck, placed on the upper part of the container, in order to prevent that, when the container is opened, generally by tearing or cutting the portion of the sheet that forms said mouth, the liquid is accidentally poured. Currently, the type of containers described above are process manufactured in vertical machines, upperly fed with a sheet made of a heat- sealable material that is conveniently folded as it is swept downward, following vertical folding lines, to form the back and the ceiling of the container, which are appropriately welded to the sheet portions wherefrom the container walls will be subsequently made by cutting the sheet. By means of this technique, the containers are produced in a horizontal position, such that, if the same machine is used to fill the containers with liquid products without turning the containers over and to subsequently close them, the above-mentioned position makes it necessary to first form a watertight receptacle, the lateral closures whereof are formed by the junction of the back and ceiling walls with the sheet portions that are to form the side walls and the lower closure whereof is formed by the junction of the sheet along what will become the junction of two facing lateral edges of the side walls of the container.

Indeed, once the back and the ceiling of the container are configured, the sheet is joined along a horizontal junction line, such that, when the sheet is cut upstream from said horizontal junction, an upperly open, watertight receptacle is produced. Closure of the opening by welding creates the junction of the other two facing lateral edges of the side walls of the container.

The last welding, that which upperly closes the container, extends along the entire length of the side walls of the container, which remain very far from each other due to the pressure exerted by the liquid upon being introduced in the watertight receptacle that constitutes the future container, once the upper edges of the sheet that forms the side walls of the container are welded. The length of the welding, the deformation undergone by the receptacle as a consequence of the filling thereof and the proximity of the liquid to the portion of the sheet that is to be welded make this operation very difficult, for which reason the full containers thus produced do not meet the desirable quality level.

On the other hand, the nozzles used to fill the containers interfere with the vertical, downward trajectory of the manufactured containers, which are produced in the form of a pile, significantly slowing the filling process. In fact, the containers must be filled one by one.

Another important aspect is that the integration of a mouth neck in the container, which is necessary in the case of stored liquid products, makes the operations to be performed during the container manufacturing process even more difficult. One observes, therefore, the lack of a method and a machine that make it possible to process manufacture this type of containers starting from a heat- sealable sheet, increasing the productivity of the known method and machine, as well as the quality of the full containers designed to store liquids which are produced.

Description of the invention

The method of the invention for the process manufacturing of erect flexible containers, starting from at least a heat-sealable sheet, and for the subsequent filling and closure thereof, overcomes the above-mentioned drawbacks. In essence, the method is characterised in that it comprises the stages described in the first claim. According to the characteristics described in said claim, the sheet is folded along horizontal folding lines in order to form a back wall and a ceiling for each container, and sheet portions are joined by welding in order to produce a closed receptacle, suitable for the storage of liquids, equipped with an open upper mouth wherethrough the product to be stored is introduced. Unlike similar methods, the sheet portions joined by welding that form the lateral seams of the manufactured containers, which are the longer junctions, are made prior to introducing the product in the containers and prior to individualising the latter; therefore, making these junctions exhibits no difficulties.

On the other hand, the last welding junction operations take place in the mouth neck of the container, which is produced in a vertical position, in such a way that they are sufficiently far from the product introduced into the container so as not to create problems due to the temperature difference between the product and the welding hot spots, or to the deformation of the side walls of the container when it is full. For this reason, the finishing of the final junctions, those which close the container, is improved, as is that of the intermediate ones which are made when the container is empty.

Likewise, the operation designed to cut the free portions in order to form the mouth neck, prior to being joined by welding, facilitates said junction since they are not subject to adopt the bent shape of the side walls, whereto they are continuously joined, once the container is full, it being possible to use welding devices designed for flat sheets.

Other characteristics of the method of the invention are described in claims 2 to 4.

A machine is also disclosed for the process manufacturing of erect flexible containers according to claim 1 , which is essentially characterised in that it comprises, in the sheet's forward direction, motor-driven rollers for the uncoiling of the heat-sealable sheet; a system designed for folding the sheet, which comprises a first sheet folding device designed to form the triple fold in an area that is shifted with respect to the middle longitudinal area; a second sheet folding device designed to form the double fold on the lateral sheet portions; guides designed to flatten the folded sheet; at least one welding station in charge of making the weldings of the lower and upper transverse walls with the adjacent side walls, respectively, of one or more containers; at least one second welding station in charge of making the two vertical welding strips in adjoining containers on each forward movement of the sheet; at least one cutting station, which comprises a cutting matrix designed to form the two halves of the mouth neck of the containers by simultaneously cutting the free, upper portions of the side walls of the corresponding containers; one cross- cutting station, adapted so as to cut the sheet in the middle area of at least one vertical welding strip, individualising the containers; one container opening station adapted so as to separate, in a direction transverse to the forward movement of the sheet, the two halves of the mouth neck of at least one container; at least one container filling station; and at least one third welding station in charge of welding the perimeter edge of the two halves of the neck of at least one container.

According to another characteristic of the invention, upstream from the sheet folding system, the machines comprises devices designed to perforate the sheet portions that make up the lower and upper transverse walls.

Brief description of the drawings

The attached drawings illustrate different stages in the embodiment of the method according to the invention, as well as a machine to implement said method. Specifically: Figs. 1 to 6 are perspective views of a portion of flat sheet during different stages of the method according to the invention; Fig. 7 is a perspective view of a container manufactured, filled and closed according to the method of the invention; Figs. 8 and 9 are views of two halves of a machine designed to implement the method according to the invention;, and

Fig. 10 is a perspective view of two flat sheet portions in the first stage of the manufacturing process.

Detailed description of the drawings

Figs. 1 to 7 represent a transverse portion of flat, heat-sealable sheet 200 at different stages of the method of the invention.

In the stage represented in Fig. 1, the sheet has been folded by making a triple fold, the first 1 , second 2 and third 3 folding lines whereof are adjacent and parallel with respect to one another, endowing the sheet with a "W-shaped cross-section, defining a first, vertical side wall 8; a lateral sheet portion 10, which is vertical and facing the first lateral sheet portion; and a lower transverse wall 11 composed of a sheet portion folded along the second 2 folding line which joins first side wall 8 and facing the lateral sheet portion 10. As can be seen, said lower transverse wall 11 is placed between the first side wall 8 and the lateral sheet portion 10, which have a different height, such that the upper edge 23 of the first wall is one level below the upper edge 24 of the lateral sheet portion 10.

In the stage represented in Fig. 2, the lateral sheet portion 10 has been folded by making a double fold along a fourth 4 and a fifth 5 folding line, which are adjacent and parallel with respect to one another. In other words, the lateral sheet portion 10 has been folded towards the first side wall 8 by making a first upper downward fold, below the fourth 4 folding line, and a second upper upward fold, above the fifth 5 folding line, correlatively defining the second side wall 12, delimited by the third and fourth folding lines, as well as an upper transverse wall 13, folded along the fifth folding line. As can be seen in said Fig. 2, the folding lines are made on the sheet in such a way that upper edges 23 and 24 of the first and second side walls are now flush.

In the stage represented in Fig. 3, the corners of the lower transverse wall 11 have been joined by welding to the respective facing areas of the first 8 and second 12 side walls. In the embodiment example, the internal sheet areas have been joined in portions 15a, 15b, 15c and 15d, which essentially have the form of a rectangular triangle, facing one another, adjoining the first 1 and third 3 folding lines; portions 15a and 15b correspond to two first sheet portions of the lower transverse wall 11 , facing each other, with corresponding facing sheet portions of the second 12 and first 8 side walls, respectively, and portions 15c and 15d correspond to two second sheet portions of lower transverse wall 11, also facing each other, with their corresponding facing sheet portions of the second 12 and first 8 side walls, respectively, the first and second portions being separated by a distance equivalent to the width of an empty, folded container.

Adjoining facing edges 16a, 16b of the first 8 and the second 12 side walls have also been joined by welding to the lower transverse wall 11 , along the first 1 and third 3 folding lines joining them.

Optionally, one may join by welding the adjoining, facing edges of the second side wall 12 and the upper transverse wall 13, along the fourth 4 folding line, although said junction is not represented in the drawings. According to Fig. 3, the comers 17 of the second side wall 12 adjoining the fourth 4 folding line have also been joined by welding to the respective facing areas of the upper transverse wall 13; and the facing portions of the first side wall 7, which are symmetrically placed with respect to the above- mentioned corners 17 of the second wall 12, have been joined by welding to the respective facing areas of the upper transverse wall 13, free upper portions 9 and 14 of the first and second side walls 8 and 12 being set above the fourth 4 folding line.

In the embodiment example, the end sheet areas have been joined in portions 17a, 17b, 17c and 17d, which essentially have the form of a rectangular triangle, facing one another, located at the level of the fourth 4 folding line; portions 17a to 17 correspond to two first sheet portions of the upper transverse wall 13, facing each other, with two facing sheet portions of the second 12 and first 8 side walls, respectively; and portions 17c and 17d correspond to two second sheet portions of the upper transverse wall 13, also facing each other, with their corresponding facing sheet portions of the second 12 and first 8 side walls, respectively, the first and second portions being separated by a distance equivalent to the width of an empty, folded container. In any event, each of vertices 18a to 18h of the joined portions are placed on one vertex of an imaginary parallelepiped. In the stage represented in Fig. 4, the first 8 and second 12 side walls have been joined by welding, by means of respective vertical welding strips 19 and 20, which extend along the entire length of said side walls, separated by a distance equivalent to the width of an empty, folded container. These welding strips are superimposed, on the upper and lower ends, on the previously made triangular junction portions, forming a receptacle 25, which is equipped with a provisional upper mouth 26, suitable to store liquid products. One should note that, in a variant of the method, which is not represented, side walls 8 and 12 are joined prior to welding end sheet areas 17a to 17d.

In the stage represented in Fig. 5, the first 9 and second 14 free upper portions of the first and second side walls 8 and 12 have been cut, forming a first 21 and a second 22 half of a mouth neck 28. In the example in Fig. 5, a first

21 and a second 22 half of a mouth neck 28 have been formed which are extended, centred with respect to vertical welding strips 19, 20, from the junction edge 27 between the upper transverse wall 13 and the first side wall 8 to the upper edges 23, 24 of the above-mentioned free upper portions 9 and 14.

In the stage represented in Fig. 6, the sheet has been vertically cut along the vertical welding strips, separating receptacle 25 from sheet 200 and producing a vertically placed individual container 6.

Similarly, the first 21 and second 22 halves of the mouth neck 28 have been separated, resulting in the opening of the provisional mouth 26 in order to perform the subsequent filling. Said Fig. 6 represents a dispenser which introduces the product to be stored through said provisional mouth 26.

In the stage represented in Fig. 7, the first 21 and second 22 halves of mouth neck 28 have been joined and the perimeter edges 30 of both halves of mouth neck 28 have been joined by welding.

In order to produce the container 6 represented in Fig. 7, it is convenient that the second 2 folding line be equidistant from the first 1 and third 3 folding lines, and that the separation distance between the fourth 4 and fifth 5 folding lines be equal to the distance between the first 1 and second 2 folding lines (see Fig. 2).

In general, the two faces of the sheets used to manufacture containers similar to those of the invention are endowed with different properties, since the face designed to be the outer face of the container will act as a medium for the printing of information or advertising, whereas the inner face will be in direct contact with the liquid stored in the container. Due to these properties, it is difficult to join by welding facing portions of the face of the sheet designed to be exposed to the exterior. In order to overcome this inconvenience, prior to the first stage, the sheet 200 is subject to a perforation stage, wherein groups of perforations are made, formed by two pairs of transversely aligned perforations; of these, perforations 32a, 32b of the first pair are made on the sheet portion that is to form the lower transverse sheet portion 11 , and separated from one another in such a way that each will be placed on one side of the second folding line 2, whereas the perforations of the second pair 33a, 33b are made on the sheet portion that will form the upper transverse sheet portion 13, and separated from one another in such a way that each will be placed on one side of the fifth folding line 5, each group of perforations being separated by a distance equivalent to the width of an empty, folded container 6. Therefore, when the operation designed to join by welding the first 8 and second 12 side walls in respective vertical welding strips 19, 20 is performed, said junctions may be made without any problem in the areas close to corners 15 and 17 wherein portions of the lower transverse wall 11 and upper transverse wall 13, corresponding to the outer face of sheet 200, face each other, since perforations 32a, 32b; 33a, 33b allow for contact between internal sheet portions, capable of being joined by welding, corresponding to side walls 8 and 12, respectively. Figs. 8 and 9 represent, in two parts, a machine for the process manufacturing of erect flexible containers 100, starting from a flat, heat-sealable sheet 200, and for the subsequent filling and closure thereof, according to the method described above. Said machine comprises, in the first part, motor- driven rollers 34 for the uncoiling of the heat-sealable sheet; perforators 35 for the sheet portions which will subsequently make up the lower 11 and upper 13 transverse portions (see Fig. 2); and a sheet folding system 36. This system comprises a first sheet folding device 37 to form the triple fold 38 in an area that is shifted with respect to the middle longitudinal area; a second sheet folding device 39 to form the double fold 40 in the lateral sheet portion 10; and guides 41 to flatten the folded sheet.

In the second part, the machine comprises a first welding station 42 in charge of performing weldings 50, 51 of the lower and upper transverse walls 11 , 13 with adjacent side walls 8 and 12, respectively, of one or more containers; a second welding station 43 in charge of performing the two vertical welding strips 19, 20 in adjoining containers in each forward movement of the sheet; a cutting station 44, which comprises a cutting matrix 45 to form the two halves 21, 22 of the mouth neck 28 of the containers by simultaneously cutting free upper portions 9, 14 of the side walls of the corresponding containers; a cross-cutting station 46, adapted so as to cut the sheet in the middle area of a vertical welding strip, individualising the containers; a container opening station 47, adapted so as to separate, in a direction transverse to the forward movement of the sheet, the two halves 21 , 22 of mouth neck 28 of a container; a container filling station 48 adapted so as to simultaneously fill two adjacent containers; and a third welding station 49 in charge of welding the perimeter edge 30 of the two halves of the neck of the filled containers. Finally, one should note that, although a method and a machine for the process manufacturing of erect flexible containers 6, 100, starting from a flat, heat-sealable sheet 200, have been described above, it is obvious that said containers 6, 100 may also be manufactured starting from two or more flat, heat-sealable sheets, originating in respective spools, although this method does not exhibit the cost and handling advantages linked to the manufacturing process from a single sheet 200.

Specifically, in the manufacturing process with two sheets, the only difference with respect to the method described above for a single sheet lies in the formation of the upper sheet portion necessary for the upper fold. The length of the first sheet is smaller than the sheet 200 used in the method described above, covering a length between the upper edge 23 of the first lateral wall 8 and the fourth 4 folding line.

The first manufacturing stage represented in Fig. 10 is similar to the one already described for Fig. 1, wherein the first sheet is folded, acquiring a W shape. In the second stage, the second sheet, which has a length equivalent to that between the fourth 4 folding line and the upper edge 24, is joined to the first sheet by welding along the edges, forming the fourth 4 folding line. In this way, a sheet is obtained that is equivalent to the sheet 200 in Fig. 2 and the manufacturing process continues according to the rest of the steps described in the method for a single sheet 200.

According to other variants, sheet 200 could be formed by two sheets joined by welding along the fifth 5 folding line, or else along the first 1, the second 2 or the third 3 horizontal folding lines, and the method for the process manufacturing of containers could also be performed in the manner described.

Claims

C L A I M S

1. Method for the process manufacturing of erect flexible containers (6, 100), starting from a flat, heat-sealable sheet (200), and for the subsequent filling and closure thereof, characterised in that it comprises the following stages: folding the sheet in a triple fold around a first (1), a second (2) and a third (3) horizontal folding lines, which are adjacent and parallel with respect to one another, defining a first, vertical side wall (8); a lateral sheet portion (10), which is parallel to, taller than and facing the wall; and a lower transverse wall (11 ) formed by a sheet portion which lowerly joins the wall and the lateral sheet portion to one another, placed between them, folded along the second folding line; - folding the lateral sheet portion towards the first wall, making a first upper downward fold, below a fourth (4) folding line, and a second upper upward fold, above a fifth (5) folding line, correlatively defining a lower portion of a second side wall (12), delimited by the third and fourth folding lines; an upper transverse wall (13), folded along the fifth folding line; and an upper portion of the second side wall, in such a way that the upper edges (23, 24) of the first and second side walls are flush; joining by welding the corners of the lower transverse wall (11 ) to the respective facing areas of the first and second side walls; joining by welding the adjoining facing edges (16a, 16b) of the first and second side walls with the lower transverse wall, along the first and third folding lines joining them; joining by welding the corners (15) of the second side wall adjoining the fourth folding line to the respective facing areas of the upper transverse wall, as well as joining, also by welding, the facing portions (17) of the first side wall, symmetrically placed with respect to said corners of the second wall, to the respective facing areas of the upper transverse wall, free upper portions (9, 14) of the first and second side walls being set above the fourth folding line; joining by welding the first (8) and second (12) side walls in respective vertical welding strips (19, 20), separated according to the width of an empty, folded container, to form a receptacle (25) that is suitable to store liquid products, equipped with a provisional upper mouth (26); cutting the first (9) and second (14) free upper portions of the first and second side walls, to form a first (21) and a second (22) half of a mouth neck (28); vertically cutting the sheet along the vertical welding strips, to separate the receptacle (25) from the sheet (200) and produce a vertically-placed individual container (6); separating the first (21) and second (22) halves of the mouth neck (28), to form the opening of the provisional mouth (26); filling the container (6) by introducing the product to be stored through the above-mentioned provisional mouth (26); and joining the first (21) and second (22) halves of the mouth neck (28) and joining, by welding, the perimeter edges (30) of both halves of the mouth neck (28).

2. Method, according to claim 1, characterised in that the second folding line (2) is equidistant from the first (1 ) and third (3) folding lines.

3. Method, according to claim 2, characterised in that the separation distance between the fourth (4) and fifth (5) folding lines is equal to the distance between the first (1 ) and second (2) folding lines.

4. Method, according to claim 1, characterised in that, prior to folding the sheet in a triple fold, the sheet (200) is subject to a perforation stage, wherein groups of perforations formed by two pairs of transversely aligned perforations are made; of these, the perforations (32a, 32b) of the first pair are made on the sheet portion that will form the lower transverse wall (11 ), and separated from one another in such a way that each will be placed on one side of the second folding line (2), whereas the perforations of the second pair (33a, 33b) are made on the sheet portion that will form the upper transverse wall (13), and separated from one another in such a way that each will be placed on one side of the fifth folding line (5), each group of perforations being separated by a distance equivalent to the width of an empty, folded container (6).

5. Erect flexible container (6, 100), produced according to the method described in claims 1 to 4.

6. Machine for the process manufacturing of erect flexible containers (100), starting from a flat, heat-sealable sheet (200), and for the subsequent filling and closure thereof, according to the method described in claim 1, characterised in that it comprises, in the direction of forward movement of the sheet: - motor-driven rollers (34) for the uncoiling of the heat-sealable sheet; a sheet folding system (36), which comprises a first sheet folding device (37) to form the triple fold (38) in an area that is shifted with respect to the middle longitudinal area; a second sheet folding device (39) to form the double fold (40) on the lateral sheet portion (10); and guides (41) to flatten the folded sheet; at least one first welding station (42) in charge of making the weldings (50, 51 ) of the lower and upper transverse walls (11, 13) with the adjacent side walls (8, 12), respectively, of one or more containers; at least one second welding station (43) in charge of making the two vertical welding strips (19, 20) in adjoining containers in each forward movement of the sheet; - at least one cutting station (44), which comprises a cutting matrix (45) to form the two halves (21 , 22) of the mouth neck (28) of the containers by simultaneously cutting the free upper portions (9, 14) of the side walls of the corresponding containers; - a cross-cutting station (46), adapted so as to cut the sheet through the middle area of at least one vertical welding strip, individualising the containers; a container opening station (47), adapted so as to separate, in a direction transverse to the forward movement of the sheet, the two halves (21, 22) of the mouth neck (28) of at least one container; at least one container filling station (48); and at least one third welding station (49) in charge of welding the perimeter edge (30) of the two halves of the neck of at least one container.

7. Machine, according to claim 6, characterised in that, upstream from the sheet folding system (36), it comprises perforation devices (35) for the sheet portions making up the lower and upper transverse walls.