APPARATUS AND PROCESS FOR DECONTAMINATING THE MOUTH OF A P ARISON OR CONTAINER IN THERMOPLASTIC MATERIAL

Technical field

The present invention relates to an apparatus and a process for decontaminating the mouth of a parison or container in thermoplastic material.

Background art

The reference sector is the bottling of so-called“sensitive” food products, that is, products that are particularly sensitive to bacteriological contamination and oxidation, such as, for example, isotonic drinks, juices, nectars, soft drinks, tea, milk-based drinks, coffee-based drinks, etc., for which the prevention of possible microbiological contamination throughout all packaging stages is of fundamental importance.

Packaging lines using aseptic technology are already known in the prior art, wherein the various operations take place in a controlled contamination environment, so that the bottled products can be stored for a prolonged period of time and have chemical/physical and organoleptic stability even at room temperature.

A modern concept of an aseptic bottling line thus envisages:

- sterilization of the parison using chemical agents or radiations;

- “aseptic” forming of the container starting with a sterilized parison;

- filling and capping of the filled container, to be carried out in a sterile environment.

Disclosure of the invention

In this regard, the Applicant has developed a forming apparatus for forming under aseptic conditions, in which the forming rotary carousel is protected by an isolation device suitable for defining a controlled- contamination environment, and the movement means for moving the carousel and moulds is located outside said isolation device (see European patent EP2246176). The preliminary sterilization stage involves all devices that come into contact with the parison subjected to forming by blowing and stretching, including for example the gripping members, the stretching rod and the blowing air circuit. The Applicant has thus developed ad hoc solutions for the stretching rod (see European Patent EP2340157) and for the blowing air circuit (see European patent application EP2643142).

In this manner, the Applicant has reached the point of developing a completely aseptic blow moulding machine and a bottling line in which the process zone for each operative unit is protected by a dedicated microbiological isolation device, from which the means for moving and handling parisons/containers is excluded (see European patent EP2279850).

The main drawback of this solution clearly lies in the marked complexity of the structure, the considerable space occupied by the sterile zones (though limited and shaped around the operative units) and in the difficulty of maintaining sterile conditions inside the isolation devices.

Furthermore, not all the manual procedures required during operation (e.g. removal of obstacles) can be performed with the use of handling gloves: in some cases, it may however be necessary to open the isolator access door, resulting in the loss of sterile conditions. Upon completion of the procedure, the sterile conditions of the environment must be restored, resulting in an evident loss of time due to downtime of the line.

In such circumstances, even procedures for format changes prove to be long and somewhat difficult.

Continuing on in reducing the volumes to be sterilized and the time needed to perform sterilization procedures, we find the solution disclosed in document EP1357081 , concerning a filling machine in which the isolator is toroidal in form and conformed to cover the areas around the neck of the containers.

This configuration originated in response to the brilliant idea of sterilizing only those surfaces of the containers that will come into contact with the filler product, that is to say, the internal surfaces of the containers or those surfaces close to the mouth, while excluding the external surfaces of the body of the containers.

Known in the sector as the “neck-ring isolator”, this solution does, however, require the arrangement of a further confinement of the body zones of the containers for the purpose of preventing leakage of the sterilizing agent into the environment external to the toroidal isolator, with resulting health risks for the operators.

The neck-ring isolator thus consists in a single volume in which the necks of the containers transit and which, however, also contains auxiliary members and elements, such as parts of the transfer stars for example. Therefore, the problems related to maintenance and/or to restoring sterile conditions remain even with the transition to a“neck-ring isolator” type of structural design.

Document EP2008667 makes known a treatment device for containers with sterile air, in which a concave shell is applied to the mouth of each container.

Aside from sterilization using chemical agents or radiation sterilization, the use of plasma for the sterilization of objects has been adopted for several decades, for example in the medical field. The plasma is obtained by passing a gas or a gas mixture between two electrodes between which an electrical discharge is generated, so that ionized particles are formed.

If one of the two electrodes is covered by an insulating material, which constitutes a dielectric barrier, it is called a DBD plasma generator, where "DBD" is the acronym for the expression "Dielectric Barrier Discharge". The dielectric barrier, which can be for example made of quartz, ceramic or glass, allows generating plasma at room temperature.

Since the first plasma generators, which comprised a vacuum chamber, technology has evolved towards the generation of atmospheric pressure plasma. For example, document no. W02007/071720 refers to a method for the sterilization of objects by means of plasma generated at atmospheric pressure.

The principal advantages associated with the use of plasma for sterilization consist of:

- treatment of objects of any shape and material;

- safety of the process, owing to the low temperatures involved and the absence of chemical agents.

The plasma is, however, a weak sterilization means for spores. To ensure effective sterilization against spores, longer application times are necessary.

In this context, the technical task underpinning the present invention is to provide an apparatus and process for decontaminating the mouth of a parison or a container in thermoplastic material, which obviate the drawbacks of the prior art as described in the foregoing.

In particular, an object of the present invention is to provide an apparatus and a process for decontaminating the mouth of a parison or a container in thermoplastic material that is more efficient at decontaminating spores compared to the known solutions.

The defined technical task and the specified objects are substantially achieved by an apparatus for decontaminating the mouth of a parison or a container in thermoplastic material, comprising:

- a concave shell configured to be applied onto the mouth of the parison or container in such a manner as to enwrap at least partially the neck of the parison or container so as to delimit a volume for treatment of the neck, said volume of treatment leaving out a bague of the parison or container;

- a supplying circuit configured to supply in said volume of treatment ozone or a plasma, that is a globally neutral ionized gas, immersed in a carrier that is constituted by vaporized hydrogen peroxide.

The supplying circuit comprises:

- a source of vaporized hydrogen peroxide;

- a plasma or ozone generator placed downstream of the source of vaporized hydrogen peroxide in such a way as to receive the vaporized hydrogen peroxide, said volume of treatment being in fluid communication with the plasma or ozone generator in such a way as to receive a mixture constituted by plasma or ozone carried by the vaporized hydrogen peroxide.

In accordance with one embodiment, the plasma or ozone generator is arranged outside said concave shell.

In particular, the decontaminating apparatus comprises a duct that allows the fluid communication between the plasma or ozone generator and the volume of treatment.

Preferably, the duct flows into the volume of treatment in such a way that it supplies the mixture around the neck of the parison or the container.

In accordance with another embodiment, the plasma or ozone generator is assembled on top of said concave shell.

In accordance with another embodiment, the supplying circuit comprises:

- a source of vaporized hydrogen peroxide;

- a plasma or ozone generator;

- a duct in which flow the vaporized hydrogen peroxide coming from the source of vaporized hydrogen peroxide and the plasma or ozone coming from the plasma or ozone generator, said duct being in fluid communication with said volume of treatment in such a way as to supply to said volume of treatment a mixture constituted by plasma or ozone carried by the vaporized hydrogen peroxide.

For example, the duct flows into the volume of treatment in such a way that it supplies the mixture around the neck of the parison or the container. Alternatively, the duct crosses the volume of treatment and flows into the mouth in such a way as to supply the mixture inside the parison or container.

The defined technical task and the specified objects are substantially achieved by a process for decontaminating the mouth of a parison or a container in thermoplastic material, comprising the steps of: - applying a concave shell onto the mouth of the parison or container in such a manner as to enwrap at least partially the neck of the parison or container so as to delimit a volume of treatment of the neck, said volume of treatment leaving out a bague of the parison or container;

- generating ozone or a plasma, that is a globally neutral ionized gas;

- generating vaporized hydrogen peroxide;

- supplying in the treatment volume ozone or plasma carried by the vaporized hydrogen peroxide.

In accordance with one embodiment, the process comprises a step of mixing the ozone or plasma with the vaporized hydrogen peroxide before supplying them to the volume of treatment.

In accordance with another embodiment, the step of supplying in the volume of treatment ozone or plasma carried by the vaporized hydrogen peroxide consists in simultaneously introducing said compositions in the volume of treatment.

In accordance with one embodiment, the process comprises a step of introducing the ozone or plasma carried by the vaporized hydrogen peroxide inside the parison or the container.

Brief description of drawings

Further characteristics and advantages of the present invention will more fully emerge from the indicative and thus non-limiting description of a preferred but not exclusive embodiment of an apparatus and a process for decontaminating the mouth of a parison or container in thermoplastic material, as illustrated in the accompanying drawings in which:

- figure 1 schematically illustrates a decontaminating apparatus for decontaminating the mouth of a preform or container in plastic material, in accordance with a first embodiment;

- figure 2 illustrates a second embodiment of the apparatus of figure 1 ;

- figure 3 illustrates a third embodiment of the apparatus of figure 1.

Detailed description of preferred embodiments of the invention

With reference to the figures, the number 1 indicates a decontaminating apparatus for decontaminating the mouth 2b of a parison or a container 2 made of thermoplastic material, such as PET or HDPE.

The decontaminating apparatus 1 comprises a concave shell 3 configured to be applied onto the mouth 2b of the individual parison or the container 2 in such a manner as to enwrap at least partially the neck 2a of the parison or container 2.

The concave shell 3 thus applied to the mouth 2b delimits a volume of treatment 4 confined around the neck 2a of the individual container 2 (or parison), thereby also protecting the internal surface thereof that will come into contact with the filling product (e.g. a beverage).

As is known, the neck of a parison does not undergo processing and therefore it coincides with the neck of the formed container.

The decontaminating apparatus 1 also comprises a supplying circuit 20 of a fluid to the volume of treatment 4.

Advantageously, the supplying circuit 20 is configured to supply to the volume of treatment 4 ozone or a plasma immersed in a carrier constituted by vaporized hydrogen peroxide.

As is known, the plasma is a gas or a mixture of globally neutral ionized gases.

In accordance with a first embodiment illustrated in figure 1 , the supplying circuit 20 comprises:

- a source of vaporized hydrogen peroxide, indicated with the number 21 ;

- an ozone or plasma generator 22, for example configured to generate DBD plasma at atmospheric pressure.

The gases used to generate the plasma can be, for example: N2/N2O, N2/O2, Ar/0 ₂ , He/02, He/N ₂ , He/0 ₂ /H ₂ 0.

The vaporized hydrogen peroxide is usually denoted by the abbreviation VHP, therefore the source 21 is briefly referred to hereinafter as VHP source.

The ozone or plasma generator 22 is placed downstream of the VHP source 21 and upstream of the volume of treatment 4.

Preferably, the volume of treatment 4 coincides with the entire volume delimited by the concave shell 3.

In particular, the ozone or plasma generator 22 has an input 22a communicating with the VHP source 21 in such a way as to receive the VHP.

A duct 23 then allows the fluid communication between the ozone or plasma generator 22 with the volume of treatment 4 in such a way as to supply the latter with a mixture constituted by the ozone or plasma immersed in a current of VHP.

Preferably, the duct 23 flows into the volume of treatment 4 in such a way that it supplies the mixture around the neck 2a of the container 2 (or parison).

In accordance with a second embodiment, illustrated in figure 2, the plasma generator 22 is mounted on the top of the concave shell 3.

In both the first and the second embodiment, the VHP flows in the ozone or plasma.

In accordance with a third embodiment, illustrated in figure 3, the mixture of ozone or plasma with the VHP takes place downstream of the ozone or plasma generator 22. Therefore two ducts are provided:

- a first duct 24 that receives the VHP from the VHP source 21 ;

- a second duct 25 that receives ozone or plasma from the ozone or plasma generator 22;

- a further duct 26 into which flow the first duct 24 and the second duct 25, the further duct 26 being in fluid communication with the volume of treatment 4 so as to supply the mixture constituted by ozone or plasma and the vaporized hydrogen peroxide to such volume of treatment 4.

Preferably, the further duct 26 flows into the volume of treatment 4 in such a way that it supplies the mixture around the neck 2a of the container 2 (or parison).

Alternatively, the further duct 26 crosses the volume of treatment 4 and flows inside the mouth 2b in such a way as to supply the mixture inside the container 2 (or parison).

Preferably, in all the embodiments the volume of treatment 4 treated extends partially around the neck 2a so as to leave the bauge 2c of the parison or container 2 outside of it.

In this context, the technical term“bague” is understood as a protuberance on the circumference of the neck 2a of the parison or container 2, the protuberance being located below the threaded zone of the neck 2a.

The concave shell 3 is preferably movable between at least one disengaging configuration and one engaging configuration of the mouth 2b of the parison or container 2.

The movement of the concave shell 3 is obtained by means of a known type.

The process for decontaminating the mouth of a parison or a container made of thermoplastic material is described below.

Such process comprises the steps of:

- applying a concave shell 3 onto the mouth 2b of the parison or container 2 in such a manner as to enwrap at least partially the neck 2a of the parison or container 2 so as to delimit a volume of treatment 4 of the neck 2a;

- generating ozone or plasma;

- generating VHP;

- supplying in the volume of treatment 4 the ozone or plasma carried by the VHP.

As shown in figures 1 -2, a step is provided to flow the VHP in the ozone or plasma in order to obtain the mixture before supplying it to the volume of treatment 4.

As shown in figure 3, the step of supplying in the volume of treatment 4 the ozone or plasma carried by the VHP consists in simultaneously introducing such compositions in the volume of treatment 4.

As shown in figure 3, it is possible to distinguish between two different supply modes of ozone/plasma and VHP, namely:

- directly into the volume of treatment 4;

- passing through the volume of treatment 4 until it flows inside the parison or the container 2.

From the above description the characteristics of the apparatus and process for decontaminating the mouth of a parison or container made of thermoplastic material, according to the present invention, will be clear, as will the resultant advantages thereof.

In particular, the use of ozone or plasma carried by VHP allows obtaining a synergistic effect of the reduction of spores and elimination of microbiological residues.