EP4613656A1

EP4613656A1 - Packaging machine configured for producing sealed packages containing a pourable product and related method

Info

Publication number: EP4613656A1
Application number: EP25156988.5A
Authority: EP
Inventors: Paolo SANIBONDI
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2024-03-06
Filing date: 2025-02-11
Publication date: 2025-09-10
Also published as: WO2025185931A8; WO2025185931A1

Abstract

There is described a packaging machine (1) configured for producing packages (2) starting from a web (4) and comprising: a web folding device (5) for folding the web (4) into a tube (3); a sealing device (6) for longitudinally sealing the tube (3); an isolation chamber (10); a delimiting element (12) designed for dividing the tube (3) in a first inner space (3a) and a second inner space (3b); a product filling pipe (11); a gas feeding device (13) configured to feed compressed gas into the second inner space (3b), so that a pressure within the second inner space (3b) is higher than a pressure within the first inner space (3a) and within the isolation chamber (10); the packaging machine (1) further comprising: a pressure sensor (15) configured to detect a variation of the pressure within the isolation chamber (10) and a control unit (16) configured to control the operation of the packaging machine (1) as a function of the detected variation of the pressure.

Description

TECHNICAL FIELD

The present invention relates to a packaging machine configured for producing sealed packages containing a pourable product, preferably a pourable food product.
The present invention also refers to a method for producing sealed packages containing a pourable product, preferably a pourable food product.

BACKGROUND ART

As it is generally known, many pourable food products, such as fruit juice, UHT (ultra-high temperature-treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
A typical example is the parallelepiped-shaped package for pourable food products known as Tetra Brik Aseptic (registered trademark), which is made by folding and sealing a laminated web of packaging material. The packaging material has a multilayer structure comprising a base layer, e.g. made of paper, covered on both sides with layers of heat-seal plastic material, e.g. polyethylene. In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material also comprises a layer of oxygen-barrier material, e.g. an aluminum foil, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material forming the inner face of the package eventually contacting the food product.
Packages of this sort are normally produced on fully automatic packaging machines, which form and fill the packages starting from a multilayer web of packaging material.
In particular, in such packaging machines a continuous tube is formed from the web of packaging material which is initially wound in a reel and fed through a plurality of unwinding rollers.
The web of packaging material is typically fed through a sterilization apparatus for sterilizing the web and then into an isolation chamber which encloses an environment controlled in sterile and/or aseptic conditions.
While advanced by the aforementioned unwinding rollers, the web is folded to form the tube by means of a known web folding unit and then sealed longitudinally. Hence, the tube is provided with a longitudinal seal before exiting the isolation chamber.
In order to perform the package forming operations, the tube is continuously fed along a first direction, normally a straight vertical direction, is filled with the sterilized food product from above and is formed, sealed and subsequently cut along equally spaced transversal cross-sections extending along a second direction, normally a direction orthogonal to the first direction.
A sequence of pillow packs is thereby obtained, which pillow packs are then fed to a folding device of the packaging machine for the final folding thereof.
Fully formed and folded packages are thereby obtained.
A packaging machine of the above type further comprises a filling system configured to fill the tube with the pourable product, while the tube is continuously formed, sealed and advanced along said first direction.
In detail, the filling system comprises a filling pipe which is inserted in, and surrounded by, the tube in formation, and which delivers the pourable product into the tube, so that a column of pourable product is defined and maintained within the tube.
In order to correctly form the pillow packs, and therefore in order to obtain finished fully-folded packages which reproduce the nominal desired configuration, it is required that the hydrostatic pressure provided within the tube is sufficiently high as otherwise irregularly shaped packages would be obtained.
According to one known configuration, such hydrostatic pressure is provided by the column of pourable product within the tube. However, depending on the package format and on the desired production speed, such column of pourable product can reach a relatively large extension in order to guarantee the needed hydrostatic pressure. Furthermore, during the starting transient of the packaging machine, the column of pourable product may have not yet reached the nominal extension required for defining the nominal hydrostatic pressure.
In order to overcome the aforementioned drawbacks, EP-A-3456638 discloses a packaging machine of the above type and comprising:

a gas feeding duct designed to feed compressed air from the isolation chamber towards the column of pourable product; and
a delimiting element or flange or plate integrally fixed to the gas feeding duct, arranged within the tube and dividing the tube in a first space being in fluidic connection with the sterile environment and a second space being arranged downstream of the first space.

The delimiting plate has a central passage through which the filling pipe extends.
The feeding duct is configured to supply the compressed air into the second space, thereby controlling the pressure therein to be greater than the pressure within the first space and the sterile environment delimited within the isolation chamber.
An overpressure is thereby defined within the second space with respect to the first space and the isolation chamber. In this way, the aforementioned pressure can be controlled, and in particular increased, so that the extension of the column of pourable product can be reduced while obtaining the same value of hydrostatic pressure.
A narrow gap is defined between the delimiting plate and the inner wall of the tube, so as to allow a smooth advancement of the tube without wearing this latter.
Hence, some of the compressed air fed into the second space returns, due to the aforementioned overpressure within the second space, into the first space, and from this latter back into the isolation chamber.
Therefore, the pressure within the isolation chamber is maintained constant throughout the packaging operation (in particular, under nominal operating conditions).
Although the packaging machines of the aforementioned type are structurally and functionally valid, the Applicant has observed that they are still open for further improvement. Therefore, a desire is felt to further improve such packaging machines.

DISCLOSURE OF INVENTION

It is therefore an object of the present invention to provide a packaging machine, and a related method, for producing sealed packages which are designed to meet the above-mentioned need in a straightforward and low-cost manner.
This object is achieved by a packaging machine and by a method as claimed in the appended independent claims. Preferred embodiments of the present invention are laid down in the appended dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view, with parts removed for clarity, of a packaging machine according to the present invention;
Figure 2 is a larger-scale, partially sectioned side view, with parts removed for clarity, of part of the packaging machine of Figure 1 showing a filling system thereof; and
Figure 3 is a diagram depicting a trend of the pressure over time within an isolation chamber of the packaging machine and a correspondent trend of the level of pourable product over time within a tube of packaging material used in the packaging machine.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1, number 1 indicates as a whole a non-limiting example of a packaging machine for producing a plurality of packages 2 containing a pourable product, preferably a pourable food product such as pasteurized or UHT milk, water, fruit juice, wine, peas, beans, etc.
In detail, packaging machine 1 is configured to form, seal and fold packages 2 starting from a web 4 of packaging material, which is initially wound in a reel 4a, and then folded into a tube 3 of packaging material, as explained below.
Preferably, the packaging material has a multilayer structure (not shown), and comprises a layer of fibrous material, e.g. paper, covered on both sides with respective layers of heat-seal plastic material, e.g. polyethylene.
In the case of aseptic packages 2 for long-storage products, such as UHT milk, the packaging material also comprises a layer of gas-and-light barrier material, e.g. aluminum foil or ethylene vinyl alcohol (EVOH) film, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material, the latter forming the inner face of package 2 eventually contacting the pourable product.
As said, the packaging material is initially provided in the form of a web 4.
Packaging machine 1 comprises conveying means (only partially shown) configured to advance web 4 along an advancement path.
As visible in Figure 1, packaging machine 1 further comprises a web folding device 5 for progressively folding the advancing web 4 into a tube 3, in a manner known and not described in detail.
Packaging machine 1 further comprises a sealing device 6 for longitudinally sealing tube 3, thereby providing tube 3 with a longitudinal seal 7.
Packaging machine 1 also comprises a forming and sealing unit (known per se and only partially visible in Figure 2) for repeatedly forming and transversally sealing tube 3 at successive cross-sections thereof, thereby obtaining a plurality of packs 2a from which packages 2 are subsequently obtained.
In detail, the forming and sealing unit is configured to sequentially impart a predetermined external shape, corresponding to a precursor of the shape of package 2, to successive longitudinal portions of tube 3, and to transversally seal tube 3 at equally spaced cross-sections.
Packaging machine 1 further comprises a folding unit (not shown) designed to fold packs 2a for obtaining packages 2.
As visible in Figure 1, packaging machine 1 comprises a filling system 8 configured for supplying pourable product into tube 3 (during its formation).
Furthermore, packaging machine 1 comprises an isolation chamber 10 enclosing a substantially sterile or aseptic environment. In particular, isolation chamber10 houses web folding device 5, the sealing device 6 and, preferably, at least part of the filling system 8.
Hence, tube 3 is provided with longitudinal seal 7 before exiting isolation chamber 10 (Figure 1).
Preferably, packaging machine 1 has an axis X along which tube 3 is fed, in use.
Axis X is parallel to a straight direction, which preferably is a straight vertical direction.
Hence, in use, tube 3 is fed along axis X, downwards, and while being filled from above by filling system 8 is formed and sealed by the forming and sealing unit, according to a manner known and not described in detail.
More specifically, tube 3 is drawn (downwards) along axis X by the forming and sealing unit in a known manner.
As visible in particular in Figure 2, filling system 8 comprises a product filling pipe 11 designed to be arranged (at least partially) within tube 3, i.e. arranged in use within tube 3 so that tube 3 surrounds filling pipe 11, and configured to supply pourable product within tube 3.
In particular, filling pipe 11 is in fluid connection or is controllable to be in fluid connection with a pourable product storage tank (not shown and known as such), which is adapted to store/provide for the pourable product, in particular the sterilized and/or sterile-processed pourable food product, to be packaged.
Preferably, at least a portion of filling pipe 11 is arranged coaxial with axis X, i.e. with tube 3.
Filling system 8 further comprises a delimiting element 12, in particular defined by a flange or plate, designed to be arranged within tube 3, i.e. arranged in use within tube 3, for dividing tube 3 in a first inner compartment or space 3a, which is open towards isolation chamber 10 (as visible in Figure 1), and a second inner compartment or space 3b arranged downstream of first space 3a with respect to the tube (downward) advancement direction along axis X.
Basically, second space 3b is delimited between delimiting element 12 and the forming and sealing unit.
More precisely, second space 3b is delimited between delimiting element 12 and the first subsequent transversal seal of tube 3 defined by the forming and sealing unit.
Filling pipe 11 is configured to supply the pourable product into second space 3b.
Filling system 8 further comprises a gas feeding device 13 configured to feed compressed gas into second inner space 3b, so that a pressure within second inner space 3b is higher than a pressure within first inner space 3a and within isolation chamber 10. In particular, gas feeding device is configured to suction gas (in particular sterile and/or aseptic air) from isolation chamber 10, to compress such gas and feed the compressed gas into second inner space 3b.
In detail, gas feeding device 13 includes:

a delivery duct 13b for feeding compressed gas to second space 3b; and, preferably, also:
a suction duct 13a for suctioning the gas from isolation chamber 10; and
pumping means 13c fluidly interposed between suction duct 13a and delivery duct 13b and configured to compress the suctioned gas.

Preferably, delivery duct 13b extends, at least in part, parallel to axis X. More preferably, delivery duct 13b is arranged coaxially to filling pipe 11.
More precisely, delivery duct 13b surrounds filling pipe 11, so that an annular flow channel 14 for the compressed gas is delimited between an outer (lateral) surface of filling pipe 11 and an inner (lateral) surface 11a of delivery duct 13b.
As visible in Figure 2, delimiting element 12 is mounted coaxially with delivery duct 13b.
Appropriately, delimiting element 12 does not contact tube 3, so that first space 3a is not fluid-tightly separated from second space 3b.
Instead, a relatively small aperture is defined between delimiting element 12 and tube 3. In such a way, it is allowed a fast advancement of tube 3 without contacting delimiting element 12, which would be detrimental to the wear of tube 3 itself.
Hence, second space 3b is fluidically connected to first space 3a.
In other words, delimiting element 12 is configured to be arranged at a non-zero distance from an inner wall 3c of tube 3, thereby allowing a recirculation (schematized in Figure 2) of some of the compressed gas from second space 3b towards first space 3a and from first space 3a back into isolation chamber 10.
In this way, the pressure within the isolation chamber 10 is maintained higher than ambient pressure. Preferably, pressure within the isolation chamber 10 is substantially constant in use (in particular, under nominal operating conditions). However, pressure within the isolation chamber 10 may vary when pressure within the second space 3b is varied. In fact, pressure within the isolation chamber 10 depends on pressure within second space 3b.
In light of the above, gas feeding device 13 allows to control the pressure in second space 3b, i.e. in the inner space of tube 3 where the pourable product is fed in use.
In this way, as it is known, it is possible to reduce the extension of the column of pourable product while maintaining the hydrostatic pressure within the second space 3b of tube 3 at the desired value.
According to an aspect of the present disclosure, packaging machine 1 comprises a pressure sensor 15 associated with isolation chamber 10 and configured to detect a variation of the pressure within isolation chamber 10 and to generate a signal correlated with the detection. In fact, pressure within isolation chamber 10 is correlated with pressure within second space 3b; so, by monitoring pressure within isolation chamber 10 it is possible to (indirectly) monitor pressure within second space 3b.
According to a further aspect of the present disclosure, packaging machine 1 further comprises a control unit 16 configured to receive the signal generated by pressure sensor 15 and to control the operation of packaging machine 1 based on the received signal and, in particular, based on the detected variation of the pressure (within isolation chamber 10).
In particular, pressure sensor 15 is configured to detect a pressure decrease within isolation chamber 10.
More in particular, pressure sensor 15 is configured to detect a pressure drop PD within isolation chamber 10.
According to the present disclosure, control unit 16 is configured to compare the detected pressure decrease (or drop) within isolation chamber 10 with a predetermined threshold pressure drop value of the pressure within isolation chamber 10.
For example, in one embodiment control unit 16 may be configured to emit a warning if the value of the detected pressure decrease (or drop) is equal to or greater than the predetermined threshold pressure drop value.
In addition, or alternatively, control unit 16 may be configured to control a stop of packaging machine 1 if the value of the detected pressure decrease (or drop) is equal to or greater than the predetermined threshold pressure drop value.
Also, control unit 16 may be configured to compare the detected pressure in isolation chamber 10 after the detected pressure decrease (or drop) with a predetermined threshold pressure value of the pressure within isolation chamber 10. Accordingly, control unit 16 is configured to control the operation of the packaging machine 1 if a value of the pressure in isolation chamber 10 after the detected pressure decrease (or drop) is equal to or below the predetermined threshold pressure value.
For example, in one embodiment, control unit 16 may be configured to emit a warning if the value of the pressure within isolation chamber 10 after the detected pressure decrease (or drop) is equal to or below the predetermined threshold pressure value.
In addition, or alternatively, control unit 16 may be configured to control a stop of packaging machine 1 if the value of the pressure within isolation chamber 10 after the detected pressure decrease (or drop) is equal to or below the predetermined threshold pressure value.
According to a further aspect of the present disclosure, control unit 16 is configured to correlate the detected pressure drop PD (or decrease) to a pressure drop within the second space 3b, and particularly to a defect in, or a failure of, or an opening in, longitudinal seal 7.
It is noted that at least a portion of second space 3b, or at least part of the portion of tube 3 delimiting second space 3b, is positioned outside isolation chamber 10.
In practice, at least a portion of second space 3b, or at least part of the portion of tube 3 delimiting second space 3b, is surrounded by the outside environment.
According to the preferred embodiment shown, the delimiting element 12 is arranged within isolation chamber 10, so that second space 3b is arranged partly within isolation chamber 10 and at least partly outside isolation chamber 10.
According to an alternative embodiment not shown, delimiting element 12 may be arranged outside of isolation chamber 10, i.e. downstream of isolation chamber 10 according to the advancement direction of tube 3, so that the second space 3b is arranged, in use, entirely outside of isolation chamber 10.
In detail, delimiting element 12, and therefore second space 3b, may be arranged between isolation chamber 10 and the forming and sealing unit.
Hence, the second space 3b, or the portion of tube 3 delimiting second space 3b, may be surrounded, in part or entirely, by the outside environment.
In light of the above, in the unlikely event that a failure or an opening is present in a region of longitudinal seal 7, when such defected region of longitudinal seal 7 exits the isolation chamber 10 and reaches the area of packaging machine 1 downstream of delimiting element 12 and upstream of the forming and sealing unit, i.e. the area at which the second space 3b is defined, the overpressure within second space 3b may force the compressed gas to leak from the defected region of longitudinal seal 7 towards the outside environment.
In particular, such compressed gas leak may occur if the defect in longitudinal seal 7 is large/significative enough to allow the outflow of compressed gas from second space 3b. In such a case, the pressure within second space 3b decreases or drops and, therefore, the amount of compressed gas available for the recirculation back into the isolation chamber 10 decreases.
As a consequence, there is a sudden pressure decrease, or pressure drop, within isolation chamber 10.
In practice, a drop in the pressure within isolation chamber 10 indicates that there is a defected region in the longitudinal seal 7.
The Applicant has observed that it is rather unlikely that such an event occurs.
Should this event occur, packaging machine 1 according to the present invention, thanks to the configuration described above and thanks to the presence of pressure sensor 15, allows to promptly and easily detect a failure in the longitudinal seal 7, and therefore to timely act (for example by following the issued warning or by automatically stopping the machine 1).
As a result, the already rather low risk of contamination is ulteriorly reduced, as well as the number of discarded packages 2 and quantity of packaging material.
Furthermore, the downtime of packaging machine 1 can be significantly reduced.
In light of the foregoing, control unit 16 is advantageously configured to issue a warning and/or to stop the packaging machine if pressure sensor 15 detects a pressure drop PD in isolation chamber 10.
Figure 3 depicts a diagram illustrating a trend of the pressure P within isolation chamber 10 over time t.
In the unlikely event of an aforementioned defected region in longitudinal seal 7, when such defected region reaches, due to the advancement of tube 3, the area outside isolation chamber 10 comprised between delimiting element 12 and the forming and sealing unit, a pressure drop PD is established within isolation chamber 10, for the reasons set forth above.
In one or more embodiments, the predetermined threshold pressure drop value is comprised between 250 Pa and 150 Pa, preferably between 220 Pa and 180 Pa, even more preferably is 200 Pa.
The Applicant has observed that such values of pressure drop PD allow an optimal management and timely detection of the defects or failures in longitudinal seal 7 without however compromising the operation of packaging machine 1 by continuously causing stops thereof.
According to an embodiment of the present disclosure, control unit 16 may be configured to compare the detected pressure decrease (or drop) within isolation chamber 10 with a first predetermined threshold pressure drop value within isolation chamber 10 and with a second predetermined threshold pressure drop value, the second predetermined threshold pressure drop value being smaller than the first predetermined threshold pressure drop value.
Accordingly, control unit 16 may be further configured to emit a warning if the value of the pressure decrease (or drop) within isolation chamber 10 is equal to or below the first predetermined threshold pressure drop value and greater than the second predetermined threshold pressure drop value.
Furthermore, control unit 16 may be configured to control a stop of packaging machine 1 if the value of the pressure drop within isolation chamber 10 is equal to or greater than the second predetermined threshold pressure drop value.
In this way, a sort of multi-level control of the operation of packaging machine 1 is implemented, whereby for a small and/or insignificant pressure decrease within isolation 10 nothing happens, for a contained pressure decrease (or drop) an alert is issued and for a significant pressure decrease (or drop) a stop of packaging machine 1 is controlled.
Also, the multi-level control allows to avoid continuous stops of packaging machine 1, which may be detrimental to a smooth production process.
As visible in Figure 2, in one embodiment filling system 8 may include a filling level sensor 17 configured to detect a level of the pourable product within second space 3b.
Hence, filling level sensor 17 is expediently arranged downstream delimiting element 12.
In particular, filling level sensor 17 is coupled with filling pipe 11.
In one embodiment, filling level sensor 17 may include a floating member of the electromagnetic type configured to detect the pourable product level by electromagnetic action, according to a manner known and not described in detail.
According to an aspect of the present disclosure, control unit 16 is configured to issue a warning and/or control the stop of packaging machine 1 if the level of pourable product in second space 3b detected by filling level sensor 17 is equal to or below a predetermined threshold level value.
In addition or alternatively, control unit 16 may be configured to issue a warning and/or control the stop of packaging machine 1 if a level decrease (or drop) LD of pourable product in second space 3b detected by filling level sensor 17 is equal to or greater than a predetermined threshold level drop value.
In other words, filling level sensor 17 is configured to detect a product level drop LD within second space 3b.
In fact, in some unlikely cases, the defect or failure in longitudinal seal 7 may define an opening in the tube 3 large enough to cause a leak of pourable product.
Hence, the presence of filling level sensor 17 contributes to a timely detection of a defected longitudinal seal 7, and adds a further safety measure, should the pressure sensor 15 not function properly.
It is noted that the warning and/or control the stop of packaging machine 1 as a function of the level of pourable product detected by filling level sensor 17 may be implemented in alternative or in addition to the above-described control the stop of packaging machine 1 as a function of the pressure in the isolation chamber 10 detected by pressure sensor 15.
The diagram of Figure 3 further depicts a diagram illustrating a trend of the pourable product level L within second space 3b over time t.
In the unlikely event of an aforementioned defected region in longitudinal seal 7, when such defected region reaches, due to the advancement of tube 3, the area outside isolation chamber 10 comprised between delimiting element 12 and the forming and sealing unit, the overpressure in second space 3b causes an outflow of pourable product from tube 3. Then, a level drop LD is established within second space 3b, for the reasons set forth above.
From the foregoing, it is clear how packaging machine 1 according to the present disclosure allows to implement a method for producing sealed packages 2 containing a pourable product by means of packaging machine 1 and starting from a web 4 of packaging material, the method comprising the steps of:

a) advancing the web 4;
b) folding the web into a tube 3;
c) longitudinally sealing the tube 3, thereby providing the tube with a longitudinal seal 7;
d) filling the tube 3 with the pourable product;
e) performing the aforementioned steps a) to d) within a substantially sterile or aseptic closed environment;
f) repeatedly forming and transversally sealing the tube 3 at successive cross-sections thereof, thereby obtaining a plurality of packs 2a from which the packages 2 are subsequently obtained;
g) dividing the tube 3 in a first inner space 3a, which is open towards said closed environment, and a second inner space 3b arranged downstream of the first inner space 3a with respect to a tube advancement direction;
h) preferably, suctioning gas from the closed environment;
i) preferably, compressing the suctioned gas;
j) feeding (the) compressed gas into the second inner space 3b, so that a pressure within the second inner space 3b is higher than a pressure within the first inner space 3a and within the closed environment;
k) recirculating some of the compressed gas from the second inner space 3b towards the first inner space 3a and from the first inner space 3a back into the closed environment, in particular so that the pressure within said closed environment is maintained substantially constant;
l) detecting a pressure within the closed environment;
m) controlling the operation of the packaging machine 1 as a function of the detected pressure.

Preferably, the method comprises the steps of:

n) comparing the detected pressure with a predetermined threshold pressure value of the pressure within the closed environment;
o) controlling the operation of the packaging machine 1 if the detected pressure is equal to or below the predetermined threshold pressure value.

In one embodiment, the method comprises the step of:
p) emitting a warning if the detected pressure is equal to or below the predetermined threshold pressure value.
In one embodiment, the method comprises the step of:
q) stopping the packaging machine 1 if the detected pressure is equal to or below the predetermined threshold pressure value.
Preferably, the method comprises the steps of:

r) detecting a pressure drop within the closed environment;
s) correlating the detected pressure drop to a defect in, or a failure of, or a opening in, said longitudinal seal 7.

In one embodiment, the method comprises the steps of:

t) detecting a level of the pourable product within the second space 3b;
u) issuing a warning and/or controlling a stop of the packaging machine 1 if the detected level is equal to or below a predetermined threshold level value.

The advantages of packaging machine 1, and of the related method, according to the present invention will be clear from the foregoing description.
In particular, packaging machine 1 according to the present invention, thanks to the configuration described above and thanks to the presence of pressure sensor 15, allows to promptly and easily detect a failure in the longitudinal seal 7, and therefore to timely act (for example by following the issued warning or by automatically stopping the machine 1).
As a result, the already rather low risk of contamination is ulteriorly reduced, as well as the number of discarded packages 2 and quantity of packaging material.
Furthermore, the downtime of packaging machine 1 can be significantly reduced.
Clearly, changes may be made to packaging machine 1 and to the related method as described herein without, however, departing from the scope of protection as defined in the accompanying claims.

Claims

Packaging machine (1) configured for producing sealed packages (2) containing a pourable product starting from a web (4) of packaging material, the packaging machine (1) comprising:
- conveying means for advancing the web (4);

- a web folding device (5) for folding the web (4) into a tube (3);

- a sealing device (6) for longitudinally sealing the tube (3), thereby providing the tube (3) with a longitudinal seal (7);

- a filling system (8) configured for supplying pourable product into the tube (3);

- an isolation chamber (10) enclosing a substantially sterile or aseptic environment and housing the web folding device (5) and the sealing device (6);

- a forming and sealing unit for repeatedly forming and transversally sealing the tube (3) at successive cross-sections thereof, thereby obtaining a plurality of packs (2a) from which the packages (2) are subsequently obtained;

- a delimiting element (12) designed to be arranged within the tube (3) for dividing the tube (3) in a first inner space (3a), which is open towards the isolation chamber (10), and a second inner space (3b) arranged downstream of the first inner space (3a) with respect to a tube (3) advancement direction;

wherein the filling system (8) comprises a product filling pipe (11) designed to be arranged within the tube (3) and configured to supply pourable product into the second inner space (3b);

the packaging machine (1) further comprising a gas feeding device (13) configured to suction gas from the isolation chamber (10), to compress such gas and to feed the compressed gas into the second inner space (3b), so that a pressure within the second inner space (3b) is higher than a pressure within the first inner space (3a) and within the isolation chamber (10);

wherein the delimiting element (12) is configured to be arranged at a non-zero distance from an inner wall (3c) of the tube (3), thereby allowing a recirculation of some of the compressed gas from the second inner space (3b) towards the first inner space (3a) and from the first inner space (3a) back into the isolation chamber (10);

wherein the packaging machine (1) further comprises:
- a pressure sensor (15) associated with the isolation chamber (10) and configured to detect a variation of the pressure within the isolation chamber (10) and to generate a signal correlated with the detection;

- a control unit (16) configured to receive said signal and to control the operation of the packaging machine (1) based on the received signal and as a function of the detected variation of the pressure.
Packaging machine (1) as claimed in claim 1, wherein the pressure sensor (15) is configured to detect a pressure decrease within the isolation chamber (10).
Packaging machine (1) as claimed in claim 2, wherein the control unit (16) is configured to control the operation of the packaging machine (1) if a value of the pressure in isolation chamber (10) after the detected pressure decrease within the isolation chamber (10) is equal to or below a predetermined threshold pressure value.
Packaging machine (1) as claimed in claim 3, wherein the control unit (10) is configured to emit a warning and/or control a stop of the packaging machine (1) if the value of the pressure within the isolation chamber (10) after the detected pressure decrease is equal to or below the predetermined threshold pressure value.
Packaging machine (1) as claimed in any of the foregoing claims, wherein said delimiting element (12) is arranged such that the second space (3b) is positioned at least partly outside the isolation chamber (10).
Packaging machine (1) as claimed in any one of the foregoing claims, wherein the pressure sensor (15) is configured to detect a pressure drop within the isolation chamber (10),
wherein the control unit (16) is configured to compare the detected pressure drop within the isolation chamber (10) with a predetermined threshold pressure drop value.
Packaging machine (1) as claimed in claim 6, wherein the control unit (16) is configured to issue a warning and/or to stop the packaging machine (1) if the detected pressure drop (PD) within the isolation chamber (10) is greater than said predetermined threshold pressure drop value.
Packaging machine (1) as claimed in claim 7, said predetermined threshold pressure drop value being comprised between 250 Pa and 150 Pa, preferably between 220 Pa and 180 Pa, even more preferably is 200 Pa.
Packaging machine (1) as claimed in any one of the foregoing claims, wherein the pressure sensor (15) is configured to detect a pressure drop (PD) within the isolation chamber (10);
and wherein the control unit (16) is configured to correlate the detected pressure drop (PD) within the isolation chamber (10) to a pressure drop in the second inner space (3b).
Packaging machine (1) as claimed in any one of the foregoing claims, wherein the filling system (8) includes a filling level sensor (17) configured to detect a level of the pourable product within the second inner space (3b);
and wherein the control unit (16) is configured to issue a warning and/or control the stop of the packaging machine (1) if the detected level is equal to or below a predetermined threshold level value.
Method for producing sealed packages (2) containing a pourable product by means of a packaging machine (1) and starting from a web (4) of packaging material, the method comprising the steps of:
a) advancing the web (4);

b) folding the web (4) into a tube (3);

c) longitudinally sealing the tube (3), thereby providing the tube (3) with a longitudinal seal (7);

d) filling the tube (3) with the pourable product;

e) performing the aforementioned steps a) to d) within a substantially sterile or aseptic closed environment enclosed by an isolation chamber (10);

f) repeatedly forming and transversally sealing the tube (3) at successive cross-sections thereof, thereby obtaining a plurality of packs (2a) from which the packages (2) are subsequently obtained;

g) dividing the tube (3) in a first inner space (3a), which is open towards said closed environment, and a second inner space (3b) arranged downstream of the second inner space with respect to a tube advancement direction;

h) suctioning gas from the closed environment;

i) compressing the suctioned gas;

j) feeding the compressed gas into the second inner space (3b), so that a pressure within the second inner space (3b) is higher than a pressure within the first inner space (3a) and within the closed environment;

k) recirculating some of the compressed gas from the second inner space (3b) towards the first inner space (3a) and from the first inner space (3a) back into the closed environment;

l) detecting a pressure within the closed environment;

m) controlling the operation of the packaging machine (1) as a function of the detected pressure.
Method as claimed in claim 11, and comprising the steps of:
n) comparing the detected pressure with a predetermined threshold pressure value of the pressure within the closed environment;

o) controlling the operation of the packaging machine (1) if the detected pressure is equal to or below the predetermined threshold pressure value.
Method as claimed in claim 12, and comprising the step of:
p) emitting a warning if the detected pressure is equal to or below the predetermined threshold pressure value.
Method as claimed in claim 12 or 13, and comprising the step of:
q) stopping the packaging machine (1) if the detected pressure is equal to or below the predetermined threshold pressure value.
Method as claimed in any of the claims 11 to 14, and comprising the steps of:
r) detecting a level of the pourable product within the second inner space (3b);

s) issuing a warning and/or controlling a stop of the packaging machine (1) if the detected level is equal to or below a predetermined threshold level value.