A method of forming and filling food containers

Technical Field

The present invention relates to a method of forming and filling containers used for food products.

In particular, the invention relates to automatic machines for the production of containers in which to package and keep liquid food products, such as fruit juices, water, milk, and the like.

Background Art

Machines of the type in question comprise a die-cutting station in which single sheets or leaves obtained from a continuous strip of multilayer food safe paper material are cut, creased and scored or perforated along predetermined lines in such a way as to generate a succession of blanks. The blanks are then transferred to a folding unit by which each one is erected.

On entering the folding unit, each blank is bent along the crease lines and the free edges of the selfsame blank are welded together, for example by means of sonotrodes, in such a manner as to fashion a tubular element generally of prismatic appearance, open at both ends.

Thereafter, the tubular elements are transferred to a further processing station where each of the single elements is associated with a respective neck of rigid plastic material, generally threaded and closable by fitting a relative screw cap.

Finally, the bottom of the tubular element is folded and sealed to create a container.

The containers formed in this way are transported by conveyor means to a filling machine on which they are sterilized by directing suitable cleansing substances in through the neck, and filled subsequently with one of the liquid food products aforementioned.

More exactly, the sterilization step consists of injecting hydrogen peroxide into each of the containers in such a way that the inside walls of the single container will be flooded by the sterilizer (hydrogen peroxide) and thus sanitized.

To ensure that no traces of the sterilizer will be left inside the container, the hydrogen peroxide is injected in the form of gas. In addition, sterile air is forced subsequently into the containers to remove any trace of the hydrogen peroxide. While effective, methods for forming and filling food containers as briefly outlined above nonetheless present certain drawbacks connected with the hygiene requirements specified in quality control standards.

In effect, notwithstanding the containers are sanitized internally, it is not impossible that they could become contaminated by external agents immediately following the disinfection step and before the subsequent filling step.

For example, the containers are transported from the sanitizing station to the filling station by means of conveyors equipped with grippers designed to take up and carry each single container by the neck.

Were the grippers to be contaminated, the container likewise could become contaminated.

During the transfer of the containers, moreover, when already sanitized but not yet filled, unwholesome air in the room where the machine is installed could find its way into the containers and cause contamination.

Again, during the step of conveying the containers from the filling station to the capping station, the liquid already batched into the container could become contaminated by external agents.

Disclosure of the Invention

Accordingly, the object of the present invention is to provide a method of forming and filling food containers in which the above noted drawbacks associated with the prior art are overcome.

In particular, it is an object of the present invention to provide a method of forming and filling food containers such as will be able to guarantee the optimum sanitization of each container manufactured. The stated objects are substantially realized in a method of forming and filling food containers according to the present invention, which includes the steps as recited in one or more of the appended claims.

Brief Description of the Drawings

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: -figure 1 shows an automatic machine, viewed schematically and in perspective, designed to implement a method of forming and filling food containers according to the present invention;

-figure 2 is an enlarged detail of the machine in figure 1 ;

-figure 3 illustrates a component of the machine in figure 2; -figure 4 is a view of the same component taken on IV-IV in figure 3.

Detailed description of the preferred embodiments of the invention

With reference to figure 1, numeral 1 denotes a machine, in its entirety, for forming and filling containers 100, and in particular a machine such as will implement a method of forming and filling containers for food products as described in the following specification. The containers 100 in question are fashioned from flat blanks 101 of multilayer paper material furnished with precreased fold lines and cut lines.

The blanks 101 are prepared at a diecutting station 2 indicated schematically in figure 1.

The single container 100 comprises a tubular body 102 of which the lateral surface is composed of four longitudinal walls arranged in two parallel pairs.

Connected to the top end of the tubular body 102 is a rigid element 103 of plastic material with an opening that can be stoppered by a closure element. The rigid element 103 is furnished with a neck, threaded externally so as to allow the application of a closure element consisting in a screw cap.

The bottom of the container 100 is sealed in such as way as to guarantee a fluid-tight closure. The machine 1 comprises a folding chamber 3 in which the containers 100 are formed by a succession of bending and sealing or welding operations performed on the blank 101.

The folding chamber 3 comprises a folding station 4 at which the blank is formed into a tubular element, open at both ends, and a rotary conveyor 5 turning on a horizontal axis.

The rotary conveyor 5 comprises two rotating wheels 5a with radial slots equispaced angularly one from the next, each designed to accommodate a respective tubular element.

The first of the two wheels 5a transfers the tubular element to the second wheel 5a.

During the rotation of the first wheel 5a, in particular, each tubular element is fitted with a relative neck, to which a screw cap will be applied.

The necks are supplied to the conveyor 5 from a respective magazine 6 (see figure 1). During the rotation of the second wheel 5a, the bottom of the container is sealed as it passes through a further processing station.

The folding chamber 3 is housed internally of a casing 7, which preferably can be opened for the purpose of accessing and inspecting the various stations making up the selfsame chamber 3. The folding chamber 3 is not sealed hermetically by the casing 7, but simply isolated from the surrounding environment.

On the outfeed side of the rotary conveyor 5, the containers 100 are taken up by transfer means 8 and advanced toward a sterilization chamber 9.

The sterilization chamber 9 extends preferably along a rectilinear horizontal path, as illustrated schematically figure 1. The transfer means 8 comprise two continuously driven looped conveyors aligned in a common plane, of which the mutually opposed branches extend parallel to the feed path followed by the containers 100 toward and through the sterilization chamber 9. Each conveyor is equipped with a plurality of grippers, placed to close on the necks of the containers, by which the selfsame containers 100 are taken up and transported at a regular distance one from the next.

Thus, the containers 100 are formed into a succession of pairs, advancing two abreast on the branches of the two conveyors. The containers 100 are transferred in this fashion to the sterilization chamber

9.

The sterilization chamber comprises an upper space 10 and a lower space 11, as illustrated in figures 3 and 4.

The upper and lower spaces are separated from one another by a baffle 12 (figure 4) allowing fluid communication between the two spaces.

The sterilization chamber presents two sets of openings 13 (one only of which is visible in figure 3), located at the opposite ends, allowing the entry and exit of the containers to and from the chamber.

The openings 13 in question will be shaped preferably to match the outline of the containers, as illustrated in figures 3 and 4.

The openings 13 also serve to allow the passage of the transport means 8, in particular the conveyors described previously, through the sterilization chamber.

The sterilization chamber 9 also comprises further openings in the top portion, that is to say coinciding with the upper space 10. The function of these further openings is to admit a fluid by which the containers 100 are sterilized.

To this end, the machine 1 comprises a plurality of injector nozzles 15 capable of movement toward and away from the necks of the containers 100 passing through the sterilization chamber 9. Preferably, the injector nozzles 15 are aligned transversely to the feed direction of the containers 100, and capable thus of vertical movement between a raised idle position, and a lowered operating position inserted into respective containers 100 advancing along the feed path.

In the example illustrated, the plurality of injector nozzles 15 includes a first group, denoted 15a, connected to a source 14 of sterilizer fluid.

The sterilizer fluid preferably will be hydrogen peroxide, and in particular hydrogen peroxide gas.

The plurality of injector nozzles 15 also includes a second group 15b connected to a source 16 of sterile air. The nozzles of the second group 15b are located downstream of the first group 15a, and will come into operation after those of the first group.

Associated with the lower space 11 of the sterilization chamber 9 are extractor means 17, preferably extractor fans, by which fluid is removed from inside the sterilization chamber 9 and exhausted under controlled conditions, that is to say through suitable filters and reservoirs, to the environment externally of the machine 1.

The machine further comprises a filling chamber 18 located downstream of the sterilization chamber 9.

The filling chamber is equipped with a plurality of filler nozzles 19, located above the conveyors of the transport means 8.

The filler nozzles 19 are aligned transversely to the feed direction of the containers 100 and capable of vertical movement between a raised idle position, and a lowered operating position inserted into respective containers 100 advancing along the feed path. Each of the filler nozzles 19 is connected by way of a respective flexible pipeline to a tank 20 containing a liquid food product such as milk or fruit juice, mineral water, or other similar fluid.

Also forming part of the machine 1 is a capping unit 21, located downstream of the filler nozzles 19 and above the filling chamber 18. The capping unit 21 comprises a device serving to take up caps 104 stacked in a magazine 22, and a device 23 by which each cap 104 is screwed onto the neck 103 of a respective container 100 (figure 1).

The screw capping device 23 is capable of alternating movement in similar fashion to the filler nozzles 19 and the injector nozzles 15, as described above. The filling chamber 18 is in fluid communication with the source 16 of sterile air, and more exactly with the same source as mentioned previously, or with another equivalent source (as schematized in figure 1).

Furthermore, the filling chamber 18 is in fluid communication with the sterilization chamber 9. Similarly, the folding chamber 3 is placed in fluid communication with the source 16 of sterile air, that is to say the same source as mentioned previously, or with another equivalent source (as schematized in figure 1).

Finally, the filling chamber 18 is placed in fluid communication with the sterilization chamber 9. The method of forming and filling food containers according to the present invention is implemented utilizing a machine as described above, in the following manner.

With the machine at standstill, that is to say with the folding chamber 3 empty and no blanks 101 yet being cut and advanced, the vacant chamber 3 is flooded with sterilizer fluid.

The sterilizer fluid will be pumped into the folding chamber 3 preferably to the point at which the chamber is saturated with the fluid.

This, advantageously, has the effect of sterilizing all the mechanical components of the folding chamber 3 described above. Once the folding chamber 3 has been thoroughly sterilized, it is filled with sterile air.

To reiterate, the folding chamber 3 is isolated from the surrounding environment, albeit not hermetically, and in fluid communication with the sterilization chamber 9. The sterilization chamber 9, and in particular the lower space 11, is in fluid communication with the surrounding environment (via the extractor means 17).

Accordingly, the sterilizer fluid in the folding chamber 3 is forced gradually, under the overpressure created by the sterile air, into the lower space 11 of the sterilization chamber 9. Consequently, the sterilizer fluid is removed ultimately from the folding chamber 3 by the extractor means 17.

The level of sterilizer fluid in the folding chamber 3 is detected by a dedicated sensor 24.

Once the level of sterilizer fluid has fallen sufficiently, the machine comes into operation and blanks 101 are directed into the folding chamber 3.

At this stage, importantly, the folding chamber 3 is filled with sterile air and any residual sterilizer fluid will be below a predetermined threshold (measured by the sensor 24).

With the mechanical parts of the folding chamber 3 sterilized in this way, the blanks 101 being folded, and similarly the partly assembled containers 100, will not be contaminated by machine parts with which they come into contact.

Sterilizer fluid is now directed into the sterilization chamber 9.

In particular, the sterilizer fluid is dispensed directly into the containers 100 by way of the injector nozzles 15, and more exactly the first set of nozzles 15a, at the same time spreading to all parts of the upper space 10 and saturating the enclosure completely.

This operation serves to sterilize the insides of the containers 100 and, at the same time, the transfer means 8.

Advantageously, the pressure of the sterilizer fluid in the upper space 10 of the sterilization chamber 9 is lower than the pressure of the environment surrounding the machine 1.

Accordingly, there is no risk of sterilizer fluid escaping from the sterilization chamber and spreading into the environment externally of the machine.

In addition, the pressure of the sterilizer fluid inside the upper space 10 is lower than the pressure of the sterile air in the folding chamber 3. In this situation, advantageously, there can be no backflow of sterilizer fluid into the folding chamber 3.

Preferably, the difference in pressure between the folding chamber 3 and the upper space 10 of the sterilization chamber 9 is such as to establish a flow of fluid (sterile air) from the folding chamber 3 toward the sterilization chamber 9, moving at a rate of between 0.2 and 5 m/s, preferably 1 m/s.

As mentioned previously, the upper space 10 of the sterilization chamber 9 is in fluid communication with the lower space 11.

The extractor means 17 draw fluid forcibly from the lower space 11 in such a way as to maintain the pressure in the upper space 10 at a given level.

Numeral 25 denotes a feedback sensor deployed preferably in the upper space 10, serving to measure the saturation level of the sterilizer fluid and pilot the operation of the extractor means 17 as appropriate.

During the operation of the extractor means 17, accordingly, the sterilizer fluid drawn from the upper space 10 will bathe the outside walls of the containers 100 (occupying the lower space 11, as described previously) and sterilize the relative surfaces.

Advancing further, the containers 100 will be engaged by the second group of injector nozzles 15b. The nozzles 15b of the second group serve to flood the insides of the containers 100 with sterile air, thereby expelling the sterilizer fluid.

Importantly, the sterilizer fluid will be removed only after the selfsame fluid has already completed its sterilizing action.

The introduction of sterile air thus serves to ensure that no traces of sterilizer fluid can be left inside the containers.

Thereafter, the containers 100 are conveyed into the filling chamber 18, where the filler nozzles 19 dispense the liquid food product into the containers, and the filled containers 100 will be closed subsequently by the capping unit 21.

Sterile air is directed into the filling chamber 18 at a pressure higher than the pressure of the fluid in the sterilization chamber 3 and higher than the ambient pressure externally of the machine 1.

Numeral 26 denotes a feedback sensor serving to measure the pressure level in the filling chamber 18 and pilot the operation of the means by which sterile air is supplied. The sterile air present in the filling chamber 18 is removed in part by the extractor means 7 and exhausted externally.

Preferably, the difference in pressure between the filling chamber 18 and the surrounding environment is such as to establish a flow of fluid (sterile air) from the filling chamber 18 to the surrounding environment, through the opening 27 (indicated in the sectional illustration of figure 4) by way of which the containers 100 leave the chamber 18, moving at a rate of between 2 and 8 m/s, preferably 4 m/s.

This solution guarantees that air outside the machine cannot penetrate the filling chamber and contaminate the containers while still open. Moreover, the difference between pressure levels in the filling chamber 18 and the sterilization chamber 9 guarantees that sterilizer fluid cannot penetrate the filling chamber 18.

To minimize the possibility of sterilizer fluid entering the filling chamber 18, this same chamber 18 will be separated preferably from the sterilization chamber 9 by a baffle 28 (figure 2) allowing passage of the containers 100 from one chamber to the other, through openings similar to the openings 13 at the entry to the sterilization chamber 9.

Self-evidently, the only "forcible" removal of fluid present in the folding chamber 3, the sterilization chamber 9 and the filling chamber 18 is brought about by the extractor means 7 located in the sterilization chamber 9, and more exactly in the lower space 11 of the chamber.

The objects stated at the outset are achieved by the present invention.

In effect, the machine 1 and the method described above will allow faultless sterilization both of the containers 100, and of mechanical parts brought into contact with the containers. In addition, the containers, once sterilized, will not be contaminated by air from outside the machine.

Similarly, containers in the process of being formed are not contaminated by external agents.