WO2013030477A1

WO2013030477A1 - Method for creating controlled atmospheres without containment on automated packaging lines

Info

Publication number: WO2013030477A1
Application number: PCT/FR2012/051701
Authority: WO
Inventors: Marc Leturmy; Fabrice Bouquin; Etienne CHARVE; Alban Poirier
Original assignee: L'air Liquide,Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2011-08-26
Filing date: 2012-07-18
Publication date: 2013-03-07
Also published as: FR2979327B1; AU2012300715A1; EP2748068B1; US20140208692A1; BR112014004390A2; ES2545856T3; CN103764500A; EP2748068A1; CN103764500B; FR2979327A1

Abstract

A method and an installation seeking to create a controlled atmosphere in the head space of a product storage container in an installation of the type in which the following measures are taken continuously: - the container is partially filled with the product to a given fill level; - the upper part of the container is placed in contact with a treatment gaseous atmosphere aimed at removing all or some of the air present in the container above said fill level and at installing the required controlled atmosphere above said level; - the upper edge of the container is sealed or closed using a suitable means; - the controlled atmosphere being installed upstream of and/or during sealing, characterized in that the controlled atmosphere is installed in an uncontained injection zone by using at least one injector of tubular type oriented in the injection zone in such a way that at least one of the components of the velocity of the sprayed gas is the opposite to the direction of travel of the containers, and in that the injector is supplied with flow that is turbulent.

Description

Process for producing controlled atmospheres without confinement on automated packaging lines

The present invention relates to the field of processes for producing modified atmospheres on articles or products, whether or not in food or in foodstuffs, in accordance with the present invention. "Modified atmosphere" means an atmosphere different from the ambient air; for example inerting the head space of bottles or containers containing a liquid at or shortly before the introduction of the cap.

The terms "headspace" or "gaseous sky" will be used indifferently in the following, a notion well known to those skilled in the art of packaging of products, particularly food products, in particular beverages and other cosmetic products, as meaning the space located above the level of liquid in the container (up to the upper neck receiving the final closure means).

In general, the invention relates to the bottling or the containerization of any type of products requiring a modified atmosphere to protect them against the resumption of oxygen, moisture, air pollutants and other dust. Examples are:

- Bottling of beverages (eg fruit, vitamin drinks, wine, mineral waters, etc.)

- Bottling of oils (food or not)

- Put in bottles, bottles or various containers of cosmetics (for example cream, shampoo, essential oils, etc.)

- Putting in bottles, bottles or various containers in the field of health (for example ointments, creams, vaccines, active ingredients, enzymes ... etc)

- Food canning

- Packaging of pot paints

- Packaging of flammable products (gasoline, solvent, ...)

- ... etc ... The realization of modified atmospheres usually consists of a partial confinement in the form of a tunnel in which the treatment gas (nitrogen, for example) is injected. Most systems are equipped with gas jets to evacuate the air from the head space which is replaced by the tunnel atmosphere. The containers or bottles circulate on a conveying system inside the tunnel. Conveyors can be very different technologies such as continuous moving belts, pilgrim conveyor systems, carousel type circular conveyors ...

These existing technologies already give good results for many cases, but may have disadvantages (see impossibilities to achieve the required specifications) in certain technical situations:

- when conveying speeds are important; for example for a 50cl beverage bottle production line, the rate reaching 40,000 bottles per hour and the conveying speed can reach 1, 6m / sec. The time required to empty the air and fill the headspace requires fairly large tunnel lengths of 50 to 70 cm or even 1 m. The longer the tunnel, the better the quality of the head space atmosphere (in terms of residual oxygen reaching for example).

the choice of an inerting tunnel can be a hindrance in some cases, even a dangerous situation in incidents downstream of it, for example at the cap plug. Cascading collisions with the inability to eject the bottles due to the presence of the bonnet can cause the bonnet to burst or unhook, the loss of cylinders and significant production shutdowns. - In the field of food, the constraints of cleanliness are important and require periodic and frequent stops to clean and sanitize the lines. The tunnels then represent risks of further contamination and therefore increase the cleaning time lines given the decontamination difficulties they generate.

the choice of these tunnel technologies has another drawback: it is not possible to treat the plugging phase. In general, over a short distance, up to 20 cm, between the end of the tunnel and the laying of the cap, the containers or bottles move in air. In this interval, the nitrogen contained in the headspace is gradually evacuated and replaced by air. This phenomenon can be major when the conveying speed is fast and the distance between the end of the tunnel and the plug is large.

against this, the solution that would be to treat until the plug is not feasible because machines placing plugs can not be included in the tunnel given the size and technology of these machines. The placement of the plugs is therefore performed under air and it is currently considered in practice, in existing installations, that the atmosphere of the head space performed upstream remains satisfactory, despite the inevitable partial mixing with the ambient air .

It can be deduced that the oxygen contents will be higher when the production rates are high, they can reach 10%, and that the residual oxygen levels in the headspace are difficult to reproduce. It is therefore conceivable that it would be advantageous to be able to have a new solution used in pl ace of such modified atmospheres, responding to such specific specifications, particularly in the case of very high rates of conveying.

As will be seen in more detail in this connection, the present invention seeks to provide a new solution for performing the treatment without confinement. This solution has been designed in particular by noting that the movement of the bottles naturally promotes the evacuation of the atmosphere from the headspace.

Considering the pressure in the head space as a reference (atmospheric pressure or substantially at this level), the moving bottle is subjected to a slight overpressure on the front part and a slight depression on the rear part.

This naturally causes a displacement of the atmosphere: the atmosphere is evacuated from behind and is replaced by air from the front (illustration of this phenomenon in Figure 1 attached).

It is then desired through the present invention to provide a configuration for:

- Take advantage of this phenomenon by ensuring that the atmosphere at the front of the container is a suitable atmosphere, such as nitrogen. In this case, the evacuation of the initial atmosphere from the head space (which may be air) takes place naturally from behind, and is replaced by the treatment atmosphere present in the room. In front of the container, for example, blown nitrogen, projected against the flow of the containers in the installation.

- To maintain the required atmosphere, for example nitrogen, on the front of the container until the introduction of the cap or other closure means of the upper neck downstream.

- At least one injector is used, the sizing is a very important element of the present invention, we will return later, which is used to achieve the flow or jet of gas. At least one, but preferably two injectors positioned on either side of the conveyor and oriented in the opposite direction to the displacement of the containers or bottles will be used.

The injector is constituted for example by a tube, of preferably square, rectangular or circular section (but this is not the case). as illustrative), as understood the objective of the invention is to work out of confinement measures, the gas thrown by the injector (s) thus opens into the ambient air surrounding the area to be treated.

The direction of the flow or jet of gas is such that at least one of its components is in the opposite direction of the direction of movement of the containers or bottles.

This application will be referred to as the "upper edge" or "opening neck" of the container, which must be understood, as will be clear to those skilled in the art, such as the upper opening of the container through which performs the filling, before this container is of course closed by any means at the end of the line. The present invention thus relates to a method for producing a controlled atmosphere at the head space of a product storage container, in a scrolling installation of the type in which the following measures are implemented:

the container is partially filled with the aid of the product to a given filling level;

the upper part of the receptacle is brought into contact with a gaseous treatment atmosphere, designed to evacuate all or part of the air present in the receptacle above said filling level and to set up, above said level, the controlled atmosphere required;

- The lid is sealed or closed with a suitable means;

the setting up of the controlled atmosphere being carried out upstream and / or during the lidding,

characterized in that the establishment of the controlled atmosphere is carried out in an unconfined injection zone, by the use of at least one tubular-type injector adapted to project towards the upper edge of the container occurring in the injection zone, the gaseous atmosphere of treatment, and oriented in the injection zone so that at least one of the components of the projected gas velocity is opposite to the direction of displacement of the containers, and that the injector is supplied with a gas flow rate to achieve a turbulent flow regime with a Reynold number between 5000 and 20000.

The injection takes place in unconfined space, without tunnel, without cowling, in the open air, thanks to the particular conditions adopted.

As indicated above, the establishment of the controlled atmosphere is carried out upstream and / or during sealing.

This takes into account the rapid displacement of the receptacles in certain producing sites, for which it is necessary to limit the space available before closure and once the controlled atmosphere has been achieved, otherwise the air will re-enter. the container, hence the fact that according to the case, the injection will be done just before and / or during the installation of the cap, cap or lid, so if necessary before and during the closing, or during the closing proper .

The present invention also relates to an installation for continuous packaging of a product in storage containers, of the type in which the following measures are implemented:

the upper part of the receptacle is brought into contact with a gaseous treatment atmosphere, designed to evacuate all or part of the air present in the receptacle above said filling level and to set up, above said level, an atmosphere controlled required;

- The lid is sealed or closed with a suitable means;

the setting up of the controlled atmosphere being carried out upstream and / or during the lidding, characterized in that the establishment of the controlled atmosphere is carried out in an unconfined injection zone, which is provided with at least one tubular type injector capable of projecting towards the upper edge of the container in the the injection zone, the gaseous treatment atmosphere, said at least one injector being oriented in the injection zone so that at least one of the components of the speed of the thrown gas is opposite to the direction of movement of the containers.

Other features and advantages of the present invention will appear more clearly in the following description, given by way of illustration but in no way limiting, in connection with the appended drawings for which:

FIG. 1 is a schematic illustration of the phenomena occurring naturally during the displacement of the containers (ie displacement of the internal atmosphere (headspace) towards the rear and its replacement by air located on the front edge of the container ).

FIG. 2 is a schematic illustration of the phenomena that are put in place by the conditions of the present invention.

FIG. 3 gives a schematic representation of an injector used for the evaluation work carried out by the Applicant, in the section in which the main parameters taken into account are mentioned.

Figure 4 is a partial schematic representation of an embodiment of the invention.

- Figure 5 is a partial schematic representation of another embodiment of the invention.

We will not return here to the phenomena illustrated in Figures 1 and 2, largely explained in the foregoing description.

Figures 4 and 5 allow to clearly visualize two modes of implementation of the invention. In both cases, the containers (already loaded with product) conveyed to a sealing or closure station by any suitable means (stopper, screw lid, etc.) are clearly visible.

In an injection zone situated very little distance upstream from the sealing station (it is preferred according to the invention not to exceed 20 cm), the containers meet the projected gas jets under flow and sizing conditions in accordance with FIG. the invention by two injectors, positioned on either side of the conveyor and oriented in the opposite direction of the displacement of the containers or bottles:

- Figure 4 illustrates a case where the two jets are directed to the same area of the conveyor.

FIG. 5 illustrates a mode in which the two jets are directed on slightly shifted zones of the conveyor, which makes it possible to interest a longer conveyor length and thus to have more time to remove the air from the head spaces.

The work carried out by the Applicant (both experimental and modeling) has shown that in such an injection configuration at the front of the containers, the quality of the atmosphere set up in the headspace ( for example the residual oxygen level reached in the headspace) will be influenced by the following parameters:

- the conditioning time, ie the time required to complete the transfer of the atmosphere from the head space and its replacement by an adequate atmosphere. This time is itself function:

o the speed of blowing against the current of the atmosphere, for example nitrogen,

o the speed of movement of the containers (in the opposite direction of the blowing),

o the distance available between gas blowing and plugging (or other means of closure)

o the volume of the headspace. - the residual oxygen content of the projected gas flow (for example nitrogen), sent to the front of the bottle or container.

And precisely, the Applicant has carried out work to study the parameters influencing the oxygen content of the flow of nitrogen projected on the containers, the objective being to favor conditions that minimize the mixing of the projected atmosphere with the ambiant air.

This work has shown that the parameters influencing the oxygen content in the nitrogen flow are:

o the distance between the injector and the area to be treated

o The speed of the treatment gas

o the flow regime

o The position of a given point of the jet with respect to the center of the jet o The section of the jet or gas flow with respect to the surface to be treated

For the avoidance of doubt, the term "surface to be treated" in the present application refers to the section of the "opening neck" of the container, i.e of the upper opening of the container through which the filling product.

This work was done using the following parameters:

- Tubular injector of diameter D

- Inerting distance between the injector and the surface to be treated: H

- Nature of the projected gas: nitrogen

- Gas velocity: v

- Distance of a point considered inside the jet with the center of the jet: d

(These parameters are displayed in the appended FIG. 3). The observed results can be summarized by the following.

1 - Influence of the distance H (between the initiator (s) and the surface to be treated) Different evaluations were carried out with a tubular injector of diameter 44mm, and for different gas velocities in turbulent flow regime (2, 4, 6, and 8 m / s).

They clearly show that the parameter of distance between the injector and the zone to be treated greatly influences the oxygen content observed at the center of the jet:

the residual oxygen content obtained increases with the distance for a given speed

- it is necessary to increase the speed to maintain the oxygen level when the injector is moved away from the surface to be treated

- for short distances (eg 5, 10 cm) the atmosphere remains very correct (100 ppm and less) regardless of the speed of the jet.

However, it is known that in practice it is rarely possible to position the injector or injectors very close to the container, because of the size of the plugging machine. It is then sometimes necessary to move the injection station away from the cork laying area, even if one makes its best efforts to keep a minimum distance, in order to obtain an atmosphere above the liquid that corresponds well. the specifications, for minimized gas consumption

As will be better detailed below, it is preferred according to the invention not to exceed 20 cm in distance, or even more preferably not to exceed 15 cm distance for the specifications of residual oxygen (the other pollutant) most severe.

Indeed, according to preferred embodiments of the invention, it will implement a distance between the injector and the area to be treated less than 20cm (including, according to the specifications of each site, for residual content objectives less than 2%) and more preferably less than 15cm (especially for objectives of less than 1% content).

2 - Influence of the flow regime The influence of the gaseous regime for a tubular injector with a diameter of 30 mm and a distance H of 15 cm was evaluated by a measurement of the oxygen contents at the center of the jet as a function of the Reynolds number.

It will be recalled that the Reynolds number is expressed by:

R = p v D / μ where

p = density (Kg / m ³ )

v = gas velocity (m / s)

D = diameter of the injector (m)

μ = dynamic viscosity (Pa s)

These studies show that it is desirable to avoid the transition between laminar and turbulent, where the oxygen content is very high (up to 3%).

The Reynolds formula shows the intervention of the speed on the one hand and the diameter on the other hand: it proves to be very difficult, especially for fairly large diameters (> 50mm), to remain stable in a laminar regime. speeds must then be very low, the low flow rates and therefore the longer conditioning time and the distance with the injector very low. It is therefore preferred according to the invention to position itself in a turbulent regime, where 5000 <Re <20000, while nevertheless preferring relatively low speeds in order to limit the consumption of gas.

3 - influence of the diameter of the injector

Oxygen concentration curves were established within the jet, as a function of the distance of the point considered at the center of the jet of gas, for different gas velocities, under the following conditions:

- D = 44mm

- H = 20cm

- v = 1, 2, 5 or 10 m / s. The following conclusions can be drawn:

- For the value of H fixed here (20 cm) the low speeds (1 and 2 m / s) do not give satisfactory atmospheric performances (residual oxygen content higher than 4%).

- There is also a degradation of the residual oxygen content as soon as the point considered in the jet away from the center of the jet.

For an area that would be desired to treat at 2% of maximum residual oxygen, it was necessary not to exceed (for the context of parameters tested here, of course) a diameter of 22 mm.

Without being bound in any way by the attempts of technical explanations which follow, one can think reasonably that when one moves away from the center of the jet, by venturi effect there is aspiration of the air around the jet which impacts then more strongly the outside of the jet in contact with the air than the inside of this jet. And we can think that the extent of the outer layer of the jet that will be impacted by the venturi effect is related to the gas velocity (thus to the Reynolds number), the higher the velocity, the thicker the impacted layer is while for small jet diameters or very high speeds a large part of the jet could be polluted by the outside air.

In this context, according to the specifications of the production site, it will be preferred according to the present invention to adopt sizing where the dimensions of the injector are significantly greater than the dimensions of the zone to be treated, and in particular where the injector section is at least twice the surface to be treated, and even more preferably at least three times greater.

Fruit juice beverage bottling tests were carried out in accordance with the present invention under the conditions summarized below:

- PET plastic bottles

- Capacity 0.5 liter, Diameter of the neck = 32mm - Rate of the line = 40000 bottles / hour

- Inerting objective: <5% of residual oxygen in the gaseous sky above the liquid

- Two offset injectors implemented, diameter 76mm

- Flow rate: 100 Nm ³ / h per injector

- Distance between the injector and the necks = 15cm

Under these conditions, a residual oxygen content of about 2% is obtained, which perfectly meets the specifications set by the site.

It should be noted that by an earlier, comparative method (inerting tunnel 1 meter long, at 100 Nm ³ / h of inerting gas consumption) it was not possible to go below 8% of residual oxygen.

Claims

claims

1. A method for producing a controlled atmosphere at the head space of a product storage container, in a scrolling installation of the type in which the following measures are implemented:

- The lid is sealed or closed with a suitable means;

characterized in that the establishment of the controlled atmosphere is carried out in an unconfined injection zone, by the use of at least one tubular-type injector adapted to project towards the upper edge of the container presenting in the injection zone, the gaseous treatment atmosphere, and oriented in the injection zone so that at least one of the components of the projected gas velocity is opposite to the direction of movement of the containers, and in that the injector is supplied with a gas flow rate enabling a turbulent flow rate with a Reynold number between 5000 and 20000 to be reached.

2. Method according to claim 1, characterized in that the diameter of the injector is such that the section of the jet which results therefrom is greater than twice the surface to be treated, preferably three times the surface to be treated.

3. Method according to claim 1 or 2, characterized in that the distance between the injector and the area to be treated is less than 20 cm, and preferably less than 15 cm.

4. Continuous packaging installation of a product in storage containers, of the type in which the following measures are implemented:

- The lid is sealed or closed with a suitable means;

characterized in that the establishment of the controlled atmosphere is carried out in an unconfined injection zone, which is provided with at least one tubular type injector adapted to project towards the upper edge of the container in the injection zone, the gaseous treatment atmosphere, said at least one injector being oriented in the injection zone so that at least one of the components of the speed of the thrown gas is opposite to the direction of movement of the containers.

5. Installation according to claim 4, characterized in that the dameter of the injector is such that the section of the jet which arises is greater than twice the surface to be treated, preferably three times the surface to be treated.

6. Installation according to claim 4 or 5, characterized in that the distance between the injector and the area to be treated is less than 20 cm, and preferably less than 15 cm.