EP4452764A1

EP4452764A1 - Apparatus for forming containers filled with a liquid and sealed

Info

Publication number: EP4452764A1
Application number: EP22835135.9A
Authority: EP
Inventors: Fabio BIRELLO; Alessandro CRISTOFORI; Maurizio Bonarelli; Federico CARLINI
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2021-12-22
Filing date: 2022-12-19
Publication date: 2024-10-30
Also published as: WO2023119120A1; IT202100032189A1

Abstract

Described herein is an apparatus for forming containers filled with a liquid and sealed, starting from a web of packaging material. The apparatus comprises: - a forming and filling unit (100) for: i) folding said web (200) about a main axis (I) to obtain a tube (202); ii) sealing along said main axis (I) said web folded to form a tube; iii) filling said tube (202) with a liquid; iv) making on said tube (202), in succession, sealing bands (204) transverse to said main axis (I) that define on said tube single semifinished containers (206), sealed and filled with said liquid; and v) separating said single semifinished containers (206) from said tube (202); - a line (10) for feeding said liquid to fill said tube (202) with said liquid; and - a unit (20) for injecting a gas into said line (10) for feeding said liquid, which comprises a nozzle body (22) that has an opening (24), defined through which is a path of flow (40) to said line (10) for feeding said liquid, said opening (24) having a width of at least 1 mm.

Description

Apparatus for forming containers filled with a liquid and sealed

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TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to an apparatus for forming containers filled with a liquid and sealed, starting from a web of packaging material.

In particular, the apparatus described herein is of the type comprising:

- a forming and filling unit for: I) folding the web about a main axis to obtain a tube; II) sealing along said main axis the web folded to form a tube; III) filling the tube with a liquid; IV) making on the tube, in succession, sealing bands transverse to the main axis that define on the tube single semifinished containers, sealed and filled with the liquid; and V) separating the single semifinished containers from the tube;

- a line for feeding the liquid to fill the tube with the liquid; and

- a unit for injecting a gas into the line for feeding the liquid.

As is known in the art, the aforesaid gas, which is injected into the liquid product, has the function of generating in each individual closed container a top space without liquid, which may be useful in order to make it possible to shake the liquid product before consumption so as to mix the compounds thereof, in the cases where these tend to stratify.

Normally, the gas used is an inert gas, for example nitrogen.

According to the prior art, the aforesaid injection unit comprises a nozzle provided with a plurality of holes having a diameter not greater than a few tens of microns.

It should now be noted that in an apparatus of the type referred to above, the line for feeding the liquid undergoes frequent flushing in order to guarantee optimal hygienic conditions.

In this context, there is hence felt the need to simplify as far as possible the operation of flushing of the line for feeding the liquid, also reducing its duration.

The aforesaid gas-injection unit of the apparatus described herein is also itself involved in the aforesaid flushing operation in so far as it gives out into the line for feeding the liquid. In this connection, the present applicant has noted that gas-mjection units according to the prior art complicate considerably the operation of flushing of the line for feeding the liquid in so far as it is necessary to remove the corresponding nozzle in order to be able to flush it, and cleaning of the nozzle in itself proves somewhat laborious. In particular, the very small holes of the nozzle represent points in which encrustations usually form, and to remove them manual intervention may be necessary.

On the other hand, the present applicant has noted that gas-injection units according to the prior art also present the drawback of having to be replaced from one application to another in so far as the number and/or size of the holes of the nozzle vary as a function of the amount of gas provided in the individual container. Also in this case it is hence necessary to intervene on the machine to replace the injection unit present in the machine with a new injection unit specific for the new application.

Likewise, for a new application that will not require injection of gas it is in any case necessary to intervene on the machine to close the communication between the line for feeding the liquid and the line for feeding the gas.

In this context, the present applicant has managed to make a gasinjection unit which has a completely new configuration that is able to overcome one or more of the aforesaid drawbacks.

In the present description and in claims annexed thereto, some terms and phrases are intended to have, except where explicitly indicated otherwise, the meaning given in the ensuing definitions.

By the phrase "path of flow" is meant a passage that can be traversed by a fluid, irrespective of its geometry and/or size.

By the phrase “outflow section” is meant a section of flow through which a fluid exits from a given path of flow.

By the term “cross section” of a given body or of a given portion of body is meant the cross section obtained in a plane orthogonal to a reference axis of the given body or of the given portion of body.

By the term "parallel" is meant a substantial parallelism between two elements, comprising both the ideal case in which these elements are arranged so as to form a zero angle with respect to one another and more frequent cases in which the two elements are arranged with respect to one another so as to form an angle that is nonzero but m any case negligible or not important for the purposes of operation of the present solution.

By the term “aligned” is meant a particular condition of parallelism in which the two elements extend along one and the same ideal straight line or in any case have respective parts that extend along one and the same ideal straight line.

According to a first aspect, the present invention concerns an apparatus for forming containers filled with a liquid and sealed, starting from a web of packaging material.

The apparatus comprises:

- preferably, a forming and filling unit, in particular for: i) folding the web about a main axis to obtain a tube; and/or ii) sealing along said main axis the web folded to form a tube; and/or iii) filling the tube with a liquid; and/or iv) making on the tube, in succession, sealing bands transverse to the main axis that define on the tube single semifinished containers, sealed and filled with the liquid; and/or v) separating the single semifinished containers from the tube;

- preferably, a line for feeding the liquid to fill the tube with the liquid; and

- preferably, a unit for injecting a gas into the line for feeding the liquid.

Preferably, the injection unit comprises a nozzle body that has an opening, defined through which is a path of flow to the line for feeding the liquid, said opening preferably having a width of at least 1 mm.

Thanks to the aforesaid characteristics, it is possible to carry out an operation of flushing of the gas-injection unit without any need to remove the aforesaid unit and in a completely automatic way, in particular by getting a flushing liquid to pass through the injection unit, which may be the same flushing liquid as the one used to flush the aforesaid line for feeding the liquid product to be packaged.

According to a second aspect, the present invention concerns a process for operating an apparatus according to the aforesaid first aspect of the invention.

The process envisages: preferably at least one work cycle for forming containers filled with a liquid and sealed, starting from a web of packaging material wound off a reel, that comprises the steps of: i) folding the web about a main axis to obtain a tube; and/or ii) sealing along said main axis said web folded to form a tube; and/or iii) filling said tube with a liquid; and/or iv) making on said tube, in succession, sealing bands transverse to said main axis that define on said tube single semifinished containers, sealed and filled with the liquid; and/or v) separating said single semifinished containers from said tube.

Preferably, filling said tube with a liquid comprises feeding the liquid to said tube through said line for feeding the liquid, and injecting a pressurized gas into said line of feed through said opening of said nozzle body of said injection unit.

Thanks to the aforesaid characteristics, it is possible to carry out an operation of flushing of the gas-injection unit, without any need to remove the aforesaid unit and in a completely automatic way, in particular by getting a flushing liquid to pass through the injection unit, which may be the same flushing liquid as the one used for flushing the aforesaid line for feeding the liquid product to be packaged.

According to one or more of the aforesaid aspects, the present invention may comprise one or more of the characteristics outlined in what follows.

In one or more embodiments, said injection unit further comprises an open/close plunger, which is mobile along a reference axis that preferably extends through the opening, to open or close the path of flow through the opening, as a function of the position of said plunger along the reference axis.

Thanks to the aforesaid characteristics, it is possible to envisage a completely closed condition of the injection unit, which may be advantageous for those applications of the apparatus in which injection of gas into the liquid product to be packaged is not required, for which applications the apparatus described herein does hence not need to be purposely prepared by removing the injection unit, as instead occurs in the solutions according to the prior art.

In one or more embodiments, said nozzle body comprises a seat in the proximity of said opening, and preferably said plunger comprises a first, closing, portion and a second, regulation, portion. Thanks to the aforesaid characteristics, the injection unit is able to regulate the flow rate of gas injected into the line for feeding the liquid to be packaged and can hence adapt its own operation to the requirements of different applications, consequently proving to be completely versatile.

Preferably, said first, closing, portion has a cross section larger than a cross section of said seat of said nozzle body and is configured to be set against said seat so as to close said path of flow through said opening.

Preferably, said second, regulation, portion has a cross section smaller than a cross section of said opening, for engaging said opening to create a path of flow between an inner surface of said opening and an outer surface of said second, regulation, portion. Preferably, said cross section of said second, regulation, portion is variable along said reference axis so as to create an outflow section of said path of flow through said opening, which is variable as a function of the position of said plunger along said reference axis.

In one or more embodiments, said plunger further comprises a third portion of maximum opening, which has a cross section smaller than said cross section of said second, regulation, portion, for engaging said opening to create a path of flow between said inner surface of said opening and an outer surface of said third portion, which has a maximum section of flow.

Thanks to the aforesaid characteristics, a wide path of flow is provided that can be easily traversed by a flushing liquid without any need to generate high pressures in the line for feeding the gas and/or the liquid.

In one or more embodiments, said first portion, said second portion, and said third portion of said plunger are arranged along said reference axis, said second portion being preferably comprised between said first portion and said third portion.

In one or more embodiments, provided on said outer surface of said second, regulation, portion is at least one recess that defines said path of flow between said inner surface of said opening and said outer surface of said second portion. Preferably, said recess extends along said reference axis and has a variable width along said reference axis.

Thanks to the aforesaid characteristics, an extremely precise regulation of the flow rate of gas is obtained.

In one or more embodiments, said outer surface of said second, regulation, portion is cylindrical, preferably centred on said reference axis. In one or more embodiments, said third portion has a cylindrical outer surface, preferably centred on said reference axis, the diameter of which is smaller than the diameter of said second portion.

In one or more embodiments, the apparatus comprises an electromechanical actuator for driving movement of said plunger along said reference axis.

In one or more embodiments, the apparatus comprises a control unit for controlling said electro-mechanical actuator as a function of a signal indicating a value of pressure of the gas, preferably upstream of said opening of said nozzle body.

In one or more embodiments, said path of flow defines a direction of flow, said reference axis is parallel to said direction of flow, and said plunger comprises a plunger body that extends along said reference axis.

In one or more embodiments, injecting a pressurized gas includes moving said plunger of said injection unit to open a path of flow through said opening of said nozzle body of said injection unit.

In one or more embodiments, the process includes regulating the flow of gas injected into said line of feed via a movement of said plunger along said reference axis that varies an outflow section of said path of flow through said opening of said nozzle body.

In one or more embodiments, the process includes a cycle of flushing of said line of feed and of said injection unit, preferably obtained via a flushing liquid. Preferably, said flushing cycle includes setting said plunger of said injection unit in a position that creates a path of flow, through said opening of said nozzle body of said injection unit, that has a maximum section of flow, and, preferably, feeding said flushing liquid through said path of flow with maximum section of flow.

In one or more embodiments, the flow of gas is divided into a plurality of distinct jets distributed about said reference axis of said plunger.

In one or more embodiments, said maximum section of flow has an annular shape that extends about said reference axis of said plunger.

Further characteristics and advantages of the present invention will emerge clearly from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which: - Figure 1 is a schematic illustration of an example of apparatus of the type described herein;

- Figure 2 illustrates a preferred embodiment of a gas-injection unit of the apparatus described herein;

- Figure 2A illustrates a detail of the injection unit of Figure 2 in an operating condition different from the one illustrated in Figure 2;

- Figure 3 illustrates a front view of a component of the injection unit of Figure 2.

In the ensuing description various specific details are illustrated, aimed at enabling an in-depth understanding of the embodiments. The embodiments may be obtained without one or more of the specific details, or with other methods, components, or materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that various aspects of the embodiment will not be obscured.

The references used herein are provided merely for convenience and hence do not define the sphere of protection or the scope of the embodiments.

As anticipated previously, the apparatus described herein operates to form containers filled with a liquid and sealed starting from a web of packaging material wound off a reel.

With reference to Figure 1, the apparatus comprises a forming and filling unit 100 for:

- folding a web 200 of packaging material about a main axis I;

- sealing the web 200 folded to form a tube along the main axis I;

- filling the tube 202, formed by the web 200, with a liquid;

- making on the tube 202, in succession, sealing bands 204 transverse to the main axis I that define on the tube 202 single semifinished containers 206, sealed and filled with the liquid; and

- separating the single semifinished containers 206 from the tube 202.

In operation, the web 200 is fed according to a movement of advance along the reference axis I.

In a way in itself known, the forming and filling unit 100 comprises at least one pair, usually two pairs, of arms 102, opposed with respect to the main axis I, which are mobile with respect to one another between an open condition and a closed condition. In particular, the arms 102 are opposed with respect to the tube 202; i.e., in other words, the tube 202 is set between the two arms 102 of one pair. Moreover, the arms 102 are driven in a reciprocating movement of translation along the main axis I, according to a working stroke from a top position to a bottom position, in the mutually closed condition, and a return stroke, from the bottom position to the top position, in the mutually open condition.

In a way in itself known, the ends 102 A of the arms 102 are configured to squeeze the tube 202, in the closed condition of the arms 102, until the inner walls of the tube are brought into mutual contact. Moreover, once again in a way in itself known, the end 102 A of one of the arms 102 of the individual pair is provided with a welding device 106 for making the transverse sealing bands 204. Once again in a way in itself known, the ends 102A of the arms are provided with shells 104 configured for defining a given containment volume of the tube, in the condition where the arms 102 are mutually closed. Finally, once again in a way in itself known, carried on the end 102A of one of the arms 102 of the individual pair is a cutting device 20 designed to make cutting lines 208, which separate the single semifinished containers 206 from the tube 202.

Furthermore, the apparatus described herein comprises a line 10 for feeding the liquid so as to fill the tube 202 with the liquid. In one or more preferred embodiments, like the one illustrated, the line of feed 10 includes a terminal stretch, which is defined by a duct 12 that extends along the main axis I and is located within the tube 202.

In addition, the apparatus described herein comprises a unit 20 for injecting a gas into the line of feed 10. In one or more preferred embodiments, like the one illustrated, the injection unit 20 is provided at a point of the feed line 10 upstream of the terminal stretch defined by the duct 12. The injection unit 20 receives the gas from a feed line 15.

With reference to Figures 2 and 2A, the injection unit 20 comprises a nozzle body 22 that has an opening 24, defined through which is a path of flow 40 to the line 10 for feeding the liquid.

In one or more preferred embodiments, like the one illustrated, the opening 24 is delimited by a cylindrical inner surface 242.

The opening 24 has a width of at least 1 mm. Preferably, the width of the opening 24 is in any case smaller than 2 cm, even more preferably comprised between 2 mm and 1 cm, even more preferably comprised between 7 mm and 9 mm.

The injection unit 20 further comprises an open/close plunger 26 mobile along a reference axis Y that extends through the opening 24, to open or close the path of flow 40 through the opening 24 itself as a function of its position along the reference axis Y.

In one or more preferred embodiments, like the one illustrated, the nozzle body 22 comprises a seat 28, which is positioned underneath the opening 24 and preferably has a frustoconical configuration.

In one or more preferred embodiments, like the one illustrated, the plunger 26 has a conformation elongated along the reference axis Y and traverses the opening 24.

In one or more preferred embodiments, like the one illustrated (see Figures 2A and 3), the plunger 26 comprises a closing portion 261, which is configured to be set against the seat 28 of the nozzle body 20 so as to close the path of flow through the opening 24. Preferably, the closing portion 261 is provided at the end of the plunger 26.

Preferably, the closing portion 261 has a frustoconical conformation corresponding to that of the seat 28 of the nozzle body 22. The cross section (in a plane orthogonal to the reference axis Y) of the closing portion 261 and the cross section of the seat 28 have a size variable along the reference axis Y, which is in any case greater than the width of the opening 24.

The plunger 26 further comprises a regulation portion 2611, which follows the closing portion 261 along the reference axis Y, starting from the end of the plunger.

In one or more preferred embodiments, like the one illustrated, the regulation portion 2611 has a cylindrical outer surface 262, the geometrical axis of which coincides with the reference axis Y. Preferably, the diameter of the cylindrical outer surface 262 is smaller than the diameter of the cylindrical inner surface 242 of the opening 24 by a difference having a value comprised between 3 pm and 7 pm. In this way, the amount of gas that can pass between the two cylindrical surfaces 262, 242 is negligible.

Moreover, provided on the cylindrical outer surface 262 is at least one recess 264, which extends along the reference axis Y and has a variable width along the axis itself, in particular increasing in the direction from the closing portion 261 to the regulation portion 2611.

The recess 264 determines, together with the cylindrical inner surface 242 of the opening 24, a path of flow 40.

In one or more preferred embodiments, provided on the cylindrical outer surface 262 of the regulation portion 2611 are a plurality of recesses distributed about the reference axis Y, which, in operation, provide as many paths of flow 40. The flow of gas delivered by the unit 20 is consequently divided into a plurality of distinct jets distributed about the reference axis Y.

Finally, the plunger 26 comprises a portion of maximum opening 26III, which is positioned downstream of the regulation portion 2611, once again with reference to a direction along the reference axis Y and starting from the end of the plunger 26.

In one or more preferred embodiments, like the one illustrated, the portion of maximum opening 26III has a cylindrical outer surface 266, the diameter of which is smaller than the diameter of the cylindrical inner surface 242 of the opening 24 for a value of at least 1 mm.

In view of the foregoing, in the raised position of the plunger 26 its closing portion 261 is set against the seat 28 of the nozzle body 22, to close completely the communication between the line 15 for feeding the gas and the line 10 for feeding the liquid.

The raised position of the plunger 26 hence corresponds to a closing position of the injection unit 20.

When, instead, the plunger 26 is lowered (see Figure 2A), through the opening 24 the path of flow 40 (or paths of flow 40) comes to be created between the cylindrical inner surface 242 of the opening 24 and the recess 264 of the second portion 2611, which sets the line 15 for feeding the gas in communication with the line 10 for feeding the liquid.

The person skilled in the sector will understand that defined between the bottom edge 242B of the cylindrical inner surface 242 and the corresponding stretch of the recess 264 is a section 42 of outflow of the gas from the opening 24. The path of flow 40 that traverses the opening 24 terminates with the outflow section 42.

As a result of the variable width of the recess 264 provided on the cylindrical outer surface 262, the outflow section 42 is variable as a function of the position of the plunger 26 along the reference axis Y ; the area of the to outflow section 42 depends, in fact, upon the width that the recess 264 has at the bottom edge 242B of the cylindrical inner surface 242 for a given position of the plunger 26 along the reference axis Y.

In view of the foregoing, by adjusting the position of the plunger 26 along the reference axis Y it is possible to adjust the outflow section 42 and hence adjust the flow rate of gas that traverses the opening 24.

The aforesaid possibility of regulation of the flow rate of gas renders the injection unit 20 readily adaptable to the requirements of the various applications (simply by adjusting the position of the plunger 26 along the reference axis Y) and thus renders it completely versatile.

The movement of the plunger 24 along the reference axis Y can be driven by an electro-mechanical actuator 50 (Figure 2).

The apparatus described herein may comprise a control unit 60 for controlling the electro-mechanical actuator.

To carry out regulation of the flow rate of gas that is injected into the line 10 for feeding the liquid, the control unit 60 may be configured for controlling the electro-mechanical actuator 50 as a function of a signal indicating a value of pressure of the gas upstream of the opening 24. For instance, for each application to which the apparatus described herein is aimed, it is possible to identify a reference pressure value, and the control unit 60 may be configured for regulating the position of the plunger 26 so as to create, at a predefined point upstream of the opening 24, a pressure equal to the reference pressure value.

Finally, when the plunger 26 is lowered further until the portion 26III is brought up to the opening 24, a path of flow 40 is instead created, characterized by maximum section of flow, which derives from the difference in diameter between the cylindrical outer surface 266 and the cylindrical inner surface 242, and may reach a width of 1 mm or more.

A path of flow 40 that is so wide may be exploited for flushing the injection unit 20, which may, for example, envisage getting a flushing liquid to pass through the injection unit.

In this way, it is not necessary to remove the injection unit, and the flushing operation can be carried out in a completely automatic way.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary, even significantly, with respect to what has been illustrated herein purely by way of non-limiting example, without thereby departing from the scope of the invention, as defined by the annexed claims.

Claims

1. An apparatus for forming containers filled with a liquid and sealed, starting from a web of packaging material, the apparatus comprising:

- a forming and filling unit (100) for: i) folding said web (200) about a main axis (I) to obtain a tube (202); ii) sealing along said main axis (I) said web folded to form a tube; iii) filling said tube (202) with a liquid; iv) making on said tube (202), in succession, sealing bands (204) transverse to said main axis (I) that define on said tube single semifinished containers (206), sealed and filled with said liquid; and v) separating said single semifinished containers (206) from said tube (202);

- a line (10) for feeding said liquid so as to fill said tube (202) with said liquid; and

- a unit (20) for injecting a gas into said line (10) for feeding said liquid, which comprises a nozzle body (22) that has an opening (24), defined through which is a path of flow (40) to said line (10) for feeding said liquid, said opening (24) having a width of at least 1 mm.

2. The apparatus according to claim 1, wherein said injection unit (20) further comprises an open/close plunger (26), which is mobile along a reference axis (Y) that extends through said opening (24), to open or close said path of flow (40) through said opening (24) as a function of the position of said plunger (26) along said reference axis (Y).

3. The apparatus according to claim 2, wherein said nozzle body (22) comprises a seat (28) in the proximity of said opening (24), and wherein said plunger (26) comprises a first, closing, portion (261) and a second, regulation, portion (2611):

- said first, closing, portion (261) has a cross section larger than a cross section of said seat (28) of said nozzle body (22) and is configured to be set against said seat (28) so as to close said path of flow (40) through said opening (24);

- said second, regulation, portion (2611) has a cross section smaller than a cross section of said opening (24), for engaging said opening (24) to create said path of flow between an inner surface (242) of said opening (24) and an outer surface (262) of said second, regulation, portion (2611), wherein said cross section of said second, regulation, portion (2611) is variable along said reference axis (Y) so as to create an outflow section (42) of said path of flow (40) through said opening (24), which is variable as a function of the position of said plunger (26) along said reference axis (Y).

4. The apparatus according to claim 3, wherein said plunger (26) further comprises a third portion of maximum opening (26III), which has a cross section smaller than said cross section of said second, regulation, portion (26III), for engaging said opening (24) to create a path of flow (40) between said inner surface of said opening and an outer surface (266) of said third portion (26III), which has a maximum section of flow.

5. The apparatus according to claim 4, wherein said first portion

(261), said second portion (2611), and said third portion (26III) of said plunger (26) are arranged along said reference axis (Y), said second portion (2611) being comprised between said first portion (261) and third portion (26III).

6. The apparatus according to claim 3, wherein provided on said outer surface (262) of said second, regulation, portion (2611) is at least one recess (264) that defines said path of flow (40) between said inner surface (242) of said opening (24) and said outer surface (262) of said second portion (2611), wherein said recess (264) extends along said reference axis (Y) and has a variable width along said reference axis (Y).

7. The apparatus according to claim 6, wherein said outer surface

(262) of said second, regulation, portion (2611) is cylindrical, in particular centred on said reference axis (Y).

8. The apparatus according to claim 7, wherein said third portion (26III) has a cylindrical outer surface (266), in particular centred on said reference axis (Y), the diameter of which is smaller than the diameter of said second portion (2611).

9. The apparatus according to any one of the preceding claims, comprising an electro-mechanical actuator (50) for driving movement of said plunger (26) along said reference axis (Y).

10. The apparatus according to claim 9, comprising a control unit (60) for controlling said electro-mechanical actuator (50) as a function of a signal indicating a value of pressure of the gas upstream of said opening (24) of said nozzle body (22).

11. The apparatus according to any one of the preceding claims, wherein said path of flow (40) defines a direction of flow, said reference axis (Y) is parallel to said direction of flow, and said plunger (26) comprises a plunger body that extends along said reference axis (Y).

12. A process for operating an apparatus according to any one of the preceding claims, which envisages: at least one work cycle for forming containers filled with a liquid and sealed, starting from a web of packaging material, comprising the steps of: i) folding the web (200) about a main axis (I) to obtain a tube (202); ii) sealing along said main axis (Y) said web (200) folded to form a tube; iii) filling said tube (202) with a liquid; iv) making on said tube (202), in succession, sealing bands (204) transverse to said main axis (I) that define on said tube (202) single semifinished containers (206), sealed and filled with said liquid; and v) separating said single semifinished containers (206) from said tube (202); wherein filling said tube (202) with a liquid comprises feeding said liquid to said tube (202) through said line (10) for feeding the liquid, and injecting a pressurized gas into said feed line (10) through said opening (24) of said nozzle body (22) of said injection unit (20).

13. The process according to claim 12, wherein injecting a pressurized gas includes moving said plunger (26) of said injection unit (20) to open a path of flow (40) through said opening (24) of said nozzle body (22) of said injection unit (20).

14. The process according to claim 13, which includes regulating the flow of gas injected into said feed line (10) via a movement of said plunger (26) along said reference axis (Y) that varies an outflow section (42) of said path of flow (40) through said opening (24) of said nozzle body (22).

15. The process according to claim 12, which includes a cycle of flushing of said feed line (10) and of said injection unit (20) obtained via a flushing liquid, wherein said flushing cycle includes setting said plunger (26) of said injection unit (20) in a position that creates a path of flow (40), through said opening (24) of said nozzle body (22) of said injection unit (20), that has a maximum section of flow, and feeding said flushing liquid through said path of flow (40) with maximum section of flow.

16. The process according to claim 12, wherein the flow of gas is divided into a plurality of distinct jets distributed about said reference axis (Y) of said plunger (26).

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17. The process according to claim 15, wherein said maximum section of flow has an annular shape that extends about said reference axis (Y) of said plunger (26).

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