IE69561B1 - Sachet forming and filling apparatus - Google Patents

Description

Sachet forming and filling apparatus This invention relates to an apparatus for producing filled sachets from webs of material by vertically forming, filling and sealing said sachets. More particularly, this invention relates to apparatus of the type known as a vertical form, till and seal liquid filling sachet machine.

So-called vertical form, fill and seal apparatus are used for the packing of a variety of products such as confectionery, food, cosmetics, pharmaceuticals, paints and decorating supplies.

In the food industry a range of products may be packed using such apparatus, for example, potato crisps, individual sachets of salad cream and soft drinks.

The present Application is particularly concerned with apparatus for producing sealed sachets of flavoured soft drinks which may subsequently be frozen and sold as iced confectionery, commonly known as cool pops, ice sticks, etc. Apparatus is known for producing these sachets from flexible plastics material. Tubes are first formed from a pair of opposed sheets of the plastics material by spaced apart vertically extending seals followed by filling of the tubes with the liquid. This results in a number of filled tubes joined together. The tubes are then separated by a cutting mechanism along the length of the vertical seals, followed by a series of cross or horizontal seals to define individual sachets. Finally, the individual sachets are separated by a horizontal cutting action. The sachet material is heated in order to create the seals and the liquid is also hot when added to the tubes.

A problem with the conventional apparatus is that a proportion of the sachets produced leak or will subsequently leak due to poor seals. This is due to the way in which the seals are formed and the way in which the sachets are separated one from the other.

Another problem with the present apparatus is that some liquid is caught up in the sealed edges. This liquid may subsequently become exposed to the atmosphere, without the sachet itself leaking. The result being that one gets mould growth on stored sachets and hence an unacceptable product.

It is an object of the present invention to provide apparatus for producing filled sachets from webs of thermoplastics material by vertically forming, filling and sealing said sachets, while at the same time overcoming the aforementioned disadvantages.

Accordingly, the invention provides an apparatus for the manufacture of filled sachets from thermoplastics material, said apparatus comprising means for sealing opposed webs of said thermoplastics material to define a series of tubes for the receipt of a filling material and adjacent tubes being spaced apart by a longitudinally extending sealed region, cutting means for separating the tubes along the longitudinally extending sealed regions, said cutting means comprising means for crunch or crush cutting the longitudinally extending sealed regions, means for cross-sealing said tubes so as to define individual sachets and a cutting device for separating said sachets, said cutting device being provided with means for rapidly cooling the cross seals prior to cutting.

The cutting device for separating the formed sachets has the advantage of producing strong and stable cross seals which do not have the tendency to fracture and leak, which is a problem with sachets produced with conventional apparatus. In the latter apparatus due inter alia to high temperature build up prior to and during the cutting operation, the seals, which at the time of cutting are very soft and pliable, have a tendency to fracture, which results in a relatively high quantity of finished sachets being rejected or, alternatively, leaking during storage with the consequent disadvantages indicated above.

In one embodiment of the invention the cutting device comprises a cutting jaw and an associated cooling jaw, for clamping the cross seal therebetween during setting and cutting thereof.

, Preferably, the cutting jaw has a blade mounted therein for movement between a retracted position and an extended position and the , associated cooling jaw has a slot therein for receiving the extended blade during a cutting action.

The advantage provided by this arrangement of the cutting device is that the cross seal is held firmly between the cutting and cooling jaws while the seal is cooling and thus setting and also while the seal is being cut through by the cutting blade.

Advantageously the means for crunch cutting the longitudinally extending sealed regions comprises a set of cutting rollers having blunt cutting edges and an opposing set of anvil rollers, such that the material is crunch cut between the cutting rollers and anvil rollers in use.

Preferably, the anvil rollers have guide means associated therewith to maintain alignment of the cutting rollers and the anvil rollers.

Thus in use the formed longitudinally extending seals pass between the cutting rollers and the anvil rollers and the material is spread apart as it separates, thus producing a sealed edge to the separated sections of said seals.

The use of crunch cutting means that the seal is compressed during the cutting operation resulting in a strong and stable seal. The use of the crunch cutting means also obviates the problem of delamination associated with a knife-cutter.

In one embodiment the means for sealing the webs of thermoplastics material to form the tubes comprises a pair of opposed * driven heated sealing rollers, the sealing rollers being cylindrical in shape and having a plurality of equally spaced, cooperating circumferential sealing ridges.

Preferably the sealing rollers are driven by a brushless servoelectric motor.

The advantage provided by this arrangement is that stretching of the material due to sudden starting and stopping characteristic of the conventional apparatus is avoided, as this type of motor ramps up or down to the desired speed or stops.

Preferably, the means for cross-sealing comprises a heated sealing jaw, having a convex sealing face, and an opposed sealing anvil having a resilient surface for engagement with said sealing jaw.

Preferably, the heated sealing jaw has a plurality of parallel grooves along the sealing face thereof so as to provide a cross seal comprising a plurality of spaced-apart sealed sections.

The advantage of this embodiment is that each cross seal is made without trapping any of the material with which the sachets are to be filled. Also the nature of the cross seal comprising as it does a plurality of spaced apart sealed sections gives added strength to the cross seals.

Preferably, the material with which the sachets are to be filled is a liquid.

Preferably, in the case were the filling material is a liquid the tubes are filled by means of nozzles mounted above the open ends of the tubes, each nozzle being connected via a flexible conduit to a supply of liquid, the flow of liquid in each conduit being controlled by valve means.

Preferably, the valve means comprises a curved anvil over which each conduit passes, a pair of rollers which move between an open position and a closed position, such that in the closed position the rollers completely restrict the liquid flow in the conduit by flattening said conduit against the curved anvil.

The advantage of this type of valve means is that when shut the liquid will not drip out of the nozzles.

Advantageously the apparatus will be provided with valve means further comprising means for detecting when the conduit has been completely restricted.

Preferably, means are provided for feeding three webs of thermoplastics material through the apparatus for the manufacture of sachets having an internal wall dividing the sachet into two separate sections.

The invention will be further illustrated by the following description of an embodiment thereof given by way of example only with reference to the accompanying Drawings in which: Fig. 1 is a perspective view of an apparatus according to the invention; Fig. 2 is a perspective view of the apparatus as shown in Fig. 1, with the front panel removed; Fig. 3 is a perspective exploded view of a cutting station of the apparatus of Fig. 1; Fig. 4 is a cross-section through line IV-IV of Fig. 3; Fig. 5 is a view of the cross-sealing station of the apparatus of Fig. 1 with the jaws in the open position; Fig. 6 is a view of the cross-sealing station of Fig. 5 with the jaws in the closed position; Fig. 7 is a view of a further cutting station of the apparatus of Fig. 1; Fig. 8 is an enlarged view of a valve means of the apparatus of Fig. 1 in the open position; and Fig. 9 is a view of the valve means of the apparatus of Fig. 8 in the closed position.

Referring to Figs. 1 and 2 of the drawings there is indicated generally at 1 an apparatus for producing filled sachets from webs of thermoplastics material by vertically forming, filling and sealing said sachets. The sachets are formed at least partially from a polyester/polyethylene laminate material, for example, of the type manufactured by Ucb Sidac; Ghent, Belgium.

The apparatus is set up for forming sachets filled with liquid fruit drinks which are subsequently frozen for sale as iced confectionery.

The apparatus comprises a front panel 2 and a rear panel 3 on which are mounted two rolls of polyester/polyethylene laminate material 4 and 6 and a roll of linear low denisty polyethylene 5. In use die web of laminate material (not shown) from roll 4 is fed through a set of fixed rollers 7 mounted on the rear panel 3 and a set of dancing rollers 8 rotatably mounted on the rear panel 3 at point 9. Similarly, the web of polyethylene material (not shown) from roll 5 is fed through a set of fixed rollers 10 and a set of dancing rollers 11 and the web of polyethylene material (not shown) from roll 6 is fed through a set of fixed rollers 12 and a set of dancing rollers 13, rotatably mounted on the rear panel 3 at point 14.

A series of tubes for receipt of the filling material is formed by a pair of driven heated sealing rollers 15,16 from the webs of laminate material and polyethylene. Each roller has four heated sealing ridges 17 arranged around the circumference of the roller.

In the apparatus as illustrated, three tubes at a time are formed by the sealing rollers 15,16, the material passing between the heated sealing ridges 17 being longitudinally sealed together.

Also in the apparatus as illustrated the web of laminate from roll 4 forms one outer wall of the sachets, the web of polyethylene material from roll 6 forms the other outer wall of the sachets and the web of laminate from roll 5 forms an internal wall dividing the sachets into two separate sections. Thus each section may be filled with a different flavoured/coioured liquid.

The sealing rollers 15,16 are driven by a brushless servoelectric motor (not shown) such as that manufactured by Parker Digiplan, United Kingdom.

The means for filling the formed tubes comprises a set of nozzles 18, only two of which are shown, mounted on a cross piece 19 connected to an upright 20 mounted on the rear panel 3 at 21.

A roller 22 mounted at the top of the upright 20 in use feeds the web of polyethylene material from roll 5 through a slot 23 in the cross piece 19 and thence between the other two webs of laminate material from rolls 4 and 6.

The nozzles 18 are connected by conduits 24 through filling valves (not shown) in housing 25, mounted on the rear panel 3, to the supply of liquid(s) (not shown).

Below the sealing rollers 15,16 is mounted a cutting station shown generally at 26 (Fig. 2) for separating the tubes along the longitudinally extending sealed regions. This station comprises a set of cutting rollers 27 and an opposing set of anvil rollers 28.

Referring to Figs. 3 and 4 part of the cutting station 26 is shown in more detail. Each cutting roller 27 is mounted on a shaft 29 and bears against the corresponding anvil roller 28. The anvil roller 28 is mounted between two arms 30 which extend from a squared guide piece 31 which is retained in use in housing 32. This arrangement prevents misalignment of the anvil roller 28 with the cutting roller 27 and thus an uneven longitudinal cut.

The set of cutting rollers 27 and the anvil rollers 28 are diespring loaded and biassed towards each other. The cutting edge 33 of each cutting roller 27 is blunt. Thus in use the laminate material is crunch cut along the longitudinally extending seals between the cutting rollers 27 and the anvil rollers 28. The blunt cutting edges 33 ensure that the edge of each sachet formed on cutting will be sealed, obviating the likelihood of delamination of the thermoplastics material.

Referring again to Fig. 2 and Figs. 6 and 7, a cross-sealing station shown generally at 34 comprises a heated sealing jaw 35 having a convex sealing face 36 with a plurality of grooves 37 therein, and an opposing sealing anvil 38 having a resilient surface 39 in the form of a rubber pressure pad, facing the sealing jaw 35. In use the sealing jaw 35 and sealing anvil 38 close together (Fig. 6) forcing the liquid in the tube 40 up and out of the sealed area. This obviates the need to stop and start the liquid flow during cutting and sealing. The grooves 37 result in a cross seal being formed which comprises a succession of spaced-apart sealed sections rather than a cross seal in the form of a single band or a number of sealed sections less than or equal to three. This arrangement provides a seal of greater strength and stability than a single band-type cross seal.

Below the cutting station 26, is mounted a cutting station shown generally at 41 for separating the formed sachets, which comprises a cutting jaw 42 and an associated cooling jaw 43. The cutting jaw 42 (Fig. 7) has a serrated cutting blade 44 mounted therein which, when extended, cuts through the cross seal 45 between the sachets and enters a slot 46 in the cooling jaw 43. The seal 45 is held between the jaws 42, during cooling and cutting. Clamping of the seal 45 is assisted by a pair of clamping pads 47. The cooling jaw 43 is cooled by a supply of cold or iced water flowing therethrough via octo-point cooling holes 48 forming part of a water cooling system.

Thus in use the filling liquid is continuously delivered into the formed tubes and the webs of laminate material move forward a sachet length at a time. As the laminate material moves forward the tubes are formed and vertically sealed. Each time the material stops a set of cross seals is formed while the previous set of cross seals is cooled and cut.

Referring to Figs. 8 and 9 there is illustrated a schematic end view of a peristaltic shut-off valve shown in the open position (Fig. 8) and in the closed position (Fig. 9). On closing, the conduit 24 is squeezed between a curved anvil 49 and a pair of rollers 50. At the same time a sensor probe 51 and fail-safe device measures the width of the squeezed tube to verify closure of the valve.

Claims (15)

CLAIMS:

1. Apparatus for the manufacture of tilled sachets from thermoplastics material, said apparatus comprising means for sealing opposed webs of said thermoplastics material to detine a series of tubes for the receipt of a tilling material and adjacent tubes being spaced apart by a longitudinally extending sealed region, cutting means for separating the tubes along the longitudinally extending sealed regions, said cutting means comprising means for crunch or crush cutting the longitudinally extending sealed regions, means for cross-sealing said tubes so as to define individual sachets and a cutting device for separating said sachets, said cutting device being provided with means for rapidly cooling the cross seals prior to cutting.

2. Apparatus as claimed in Claim 1, wherein the cutting device comprises a cutting jaw and an associated cooling jaw, for clamping the cross seal therebetween during setting and cutting thereof.

3. Apparatus as claimed in Claim 2, wherein the cutting jaw has a blade mounted therein for movement between a retracted position and an extended position and the associated cooling jaw has a slot therein for receiving the extended blade during a cutting action.

4. Apparatus as claimed in any one of Claims 1-3, wherein the means for crunch cutting the longitudinally extending sealed regions comprises a set of cutting rollers having blunt cutting edges and an opposing set of anvil rollers, such that the material is crunch cut between the cutting rollers and anvil rollers in use.

5. Apparatus as claimed in Claim 4, wherein the anvil rollers have guide means associated therewith to maintain alignment of the cutting rollers and the anvil rollers.

6. Apparatus as claimed in any preceding claim, wherein the means for sealing the webs of thermoplastics material to form the tubes comprises a pair of opposed driven heated sealing rollers, the sealing rollers being cylindrical in shape and having a plurality of equally spaced, cooperating circumferential sealing ridges.

7. Apparatus as claimed in Claim 6, wherein the sealing rollers are driven by a brushless servoelectric motor.

8. Apparatus as claimed in any preceding claim, wherein the means for cross-sealing comprises a heated sealing jaw, having a convex sealing face, and an opposed sealing anvil having a resilient surface for engagement with said sealing jaw.

9. Apparatus as claimed in Claim 8, wherein the heated sealing jaw has a plurality of parallel grooves along the sealing face thereof, so as to provide a cross seal comprising a plurality of spaced apart sealed sections.

10. Apparatus as claimed in any preceding claim, wherein the filling material is a liquid.

11. Apparatus as claimed in Claim 10, wherein the tubes are filled by means of nozzles mounted above the open ends of the tubes, each nozzle being connected via a flexible conduit to a supply of liquid, the flow of liquid in each conduit being controlled by valve means.

12. Apparatus as claimed in Claim 11, wherein said valve means comprises a curved anvil over which each conduit passes, a pair of rollers which move between an open position and a closed position, such that in the closed position the rollers completely restrict the liquid flow in the conduit by flattening said conduit against the curved anvil.

13. Apparatus as claimed in Claim 12, further comprising means for detecting when the conduit has been completely restricted.

14. Apparatus as claimed in any preceding claim, wherein means are provided for feeding three webs of thermoplastics material through the apparatus for the manufacture of sachets having an internal wall dividing the sachet into two separate sections.

15. Apparatus as claimed in Claim 1, substantially as hereinbefore described with particular reference to and as illustrated in 5 the accompanying Drawings.