Patent Description:
The present invention also relates to a method for producing packages of a pourable product, in particular a pourable food product.

As is known, many liquid or 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 liquid or pourable food products known as Tetra Brik Aseptic (registered trademark), which is made by sealing and folding laminated strip packaging material. The packaging material has a multilayer structure comprising a base layer, e.g. 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 (an oxygen-barrier layer), 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 advance a web of packaging material from a magazine unit through a sterilization apparatus for sterilizing the web of packaging material and into an isolation housing (a closed and at least in part sterile environment) in which the sterilized web of packaging material is maintained and advanced. An example of packaging machine is disclosed in patent document <CIT>. During advancement of the web of packaging material through a main chamber of the isolation housing, the web of packaging material is folded and sealed longitudinally to form a tube having a longitudinal seal, which is further fed along a vertical advancing direction into and through an auxiliary chamber of the isolation housing.

In order to complete the forming operations, the tube is filled with a sterilized or sterile-processed pourable product, in particular a pourable food product, and is subsequently formed for at least partially defining the final shape of the package, transversally sealed and subsequently cut along equally spaced transversal cross sections within a package forming unit of the packaging machine during advancement along the vertical advancing direction.

Pillow packages are so obtained within the packaging machine, each pillow package having a longitudinal sealing band, a top transversal sealing band and a bottom transversal sealing band.

It is known that shortly after the sealing the longitudinal seal of the tube is still warm and, thus, is weaker than the fully cooled one. This is typically the case with the tube advancing within a downstream portion of the main chamber and an upstream portion of the auxiliary chamber. Therefore, it is required to control the overall process such to avoid or to at least limit the possibility of the longitudinal seal collapsing (i.e. to open and/or losing its integrity) during the advancement of the tube as a result of the forces acting on the tube itself.

In the unlikely case that the longitudinal seal should collapses (i.e. the tube opens and/or loses its integrity), it is necessary to stop producing and reestablish production under aseptic conditions. The need is felt to render such operations quicker.

Therefore, the need is felt to provide for packaging machines, which allow a timely detection of the longitudinal seal's collapse.

It is therefore an object of the present invention to provide an improved packaging machine to overcome, in particular which allows a timely detection of the occurrence of a collapse of the longitudinal seal.

It is a further object of the present invention to provide a method for producing packages to overcome, in particular which allows a timely detection of the occurrence of a collapse of the longitudinal seal.

According to the present invention, there is provided a packaging machine and a method for producing sealed packages according to the independent claims.

Preferred embodiments are claimed in the dependent claims.

Number <NUM> indicates as a whole a packaging machine for producing packages <NUM>, in particular sealed packages <NUM>, of a pourable product, in particular a pourable food product such as pasteurized milk, fruit juice, wine, tomato sauce, etc., from a tube <NUM> of a web of packaging material <NUM>. In particular, in use, tube <NUM> extends along a longitudinal axis, in particular having a vertical orientation.

Web of packaging material <NUM> comprises at least a layer of fibrous material, in particular paper or cardboard, covered on both sides with respective layers of heat-seal plastic material, e.g. polyethylene.

Web of packaging material <NUM> may also comprise a layer of gas- and light-barrier material, e.g. aluminum foil or ethylene vinyl alcohol (EVOH) film, and at least a first layer and a second layer of heat-seal plastic material. Preferentially, the layer of gas- and light-barrier material being superimposed on the first layer of heat-seal plastic material, and is in turn covered with the second layer of heat-seal plastic material. The second layer of heat-seal plastic material may form the inner face of package <NUM> eventually contacting the filled pourable food product.

More specifically, web of packaging material <NUM> may comprise a first face and a second face, in particular the first face being the face of web of packaging material <NUM> forming the inner face of the formed package <NUM> eventually contacting the filled pourable food product.

A typical package <NUM> obtained by packaging machine <NUM> comprises a longitudinal seam portion and a pair of transversal sealing bands, in particular a transversal top sealing band and a transversal bottom sealing band.

With particular reference to <FIG>, packaging machine <NUM> may be configured to advance web of packaging material <NUM> along a web advancement path P, preferably to sterilize web of packaging material <NUM> during advancement along path P, to form tube <NUM> from web of packaging material <NUM> and to fill tube <NUM> and, preferentially to form single packages <NUM> from the filled tube <NUM>.

Preferentially, packaging machine <NUM> may comprise:.

In particular, in use, main chamber <NUM> is kept under aseptic conditions. In particular auxiliary chamber <NUM> is not under aseptic conditions. In other words, while main chamber <NUM> is an aseptic chamber and/or is configured to be operated under aseptic conditions, auxiliary chamber <NUM> is not an aseptic chamber.

In particular, tube forming and sealing device <NUM> may be configured to form tube <NUM> having a longitudinal seal portion <NUM>. Even more particular, tube forming and sealing device <NUM> may be configured to overlap, in use, the lateral edges of web of packaging material <NUM> and to seal the overlapping lateral edges so as to form the longitudinal seal portion <NUM>. The longitudinal seal portion <NUM> extends parallel to the tube advancement path Q.

Preferentially, packaging machine <NUM> also comprises a package forming unit <NUM> configured to at least form and transversally seal tube <NUM>, preferentially to also transversally cut tube <NUM>, between successive packages <NUM>, in particular during advancement of tube <NUM> along tube advancement path Q.

Packaging machine <NUM> may also comprise a magazine unit configured to host web of packaging material <NUM> at a host station <NUM>. In particular, the magazine unit may comprise at least two loading platforms, each one configured to retain one respective bobbin of web of packaging material <NUM>. Even more particular, in use, while one loading platform may retain the bobbin having web of packaging material <NUM> in use, while the other loading platform may retain a bobbin of a new web of packaging material <NUM>.

Additionally, packaging machine <NUM>, in particular the magazine unit, may also comprise a splicing device configured to splice the web of packaging material <NUM> in use (namely, the currently used web of packaging material <NUM>), with the new web of packaging material <NUM>. In more detail, the splicing device may be configured to splice a leading portion of the new web of packaging material <NUM> to a trailing portion of the web of packaging material <NUM> in use.

In particular, in use, splicing of the web of packaging material <NUM> in use and the new web of packaging material <NUM> may define a spliced portion of the web of packaging material <NUM> formed as a result of the splicing. The spliced portion of web of packaging material <NUM> comprises two superimposed layers of fibrous layers. In other words, the thickness of the spliced portion is larger, in particular (substantially) twice as large, as the thickness of the other portions of web of packaging material <NUM>.

Preferentially, packaging machine <NUM> may also comprise a sensor device having one or more position sensors <NUM> configured to determine the spliced portion of web of packaging material <NUM>, in particular for determining a relative position of the spliced portion along web advancement path P. As will be explained in more detail further below, knowing the relative position of the spliced portion of web of packaging material <NUM> along web advancement path P is useful to determine a collapse of the longitudinal portion of the tube more precisely.

Advantageously, packaging machine <NUM> may also comprise a pressure control device <NUM> configured to control the pressure within at least portions of isolation housing <NUM>, in particular within at least main chamber <NUM> and, preferentially also within auxiliary chamber <NUM>.

According to some preferred embodiments, pressure control device <NUM> is configured to control a first pressure p1 within main chamber <NUM> and a second pressure p2 different from first pressure p1 within auxiliary chamber <NUM>. In particular, first pressure p1 is higher than second pressure p2.

In particular, in this way pressure control device <NUM> is configured to control first pressure p1 and second pressure p2 such that contaminations are prevented to enter into main chamber <NUM>.

In a preferred non-limiting embodiment, pressure control device <NUM> may be configured to control first pressure p1 to range between <NUM> mbar to <NUM> mbar above ambient pressure, preferentially <NUM> mbar to <NUM> mbar above ambient pressure, even more preferentially <NUM> mbar to <NUM> mbar above ambient pressure.

Moreover, pressure control device <NUM> may be configured to control a pressure difference Δp between first pressure p1 and second pressure p2 (Δp = p1 - p2). In particular, the pressure control device <NUM> may be configured to maintain pressure difference Δp at a desired and/or defined pressure difference value Δpdes.

According to some preferred non-limiting embodiment, the desired and/or defined pressure difference value Δpdes may be larger than <NUM> mbar, in particular larger than <NUM> mbar, even more particular at least <NUM> mbar.

According to some possible non-limiting embodiments, the desired and/or defined pressure difference value Δpdes may be smaller than <NUM> mbar, in particular smaller than <NUM> mbar, even more particular smaller than <NUM> mbar.

According to a most preferred embodiment, the desired and/or defined pressure difference value Δpdes may equal <NUM> mbar.

It should be noted that the pressure difference Δp is subject to inherent fluctuations around the desired and/or defined pressure difference value Δpdes as e.g. visible in the first part of the curve representing the time-dependent course of pressure difference Δp.

Packaging machine <NUM> may also comprise a pressure measuring device <NUM> configured to measure, in particular to continuously measure, pressure difference Δp. In particular, pressure measuring device <NUM> comprises a first pressure measuring unit <NUM> configured to measure the pressure in the main chamber <NUM> and a second pressure measuring unit (not illustrated) configured to measure the pressure in the auxiliary chamber <NUM>.

Preferentially, pressure measuring device <NUM> comprises at least one differential pressure sensor configured to measure pressure difference Δp between the main chamber <NUM> and the auxiliary chamber <NUM>. The differential pressure sensor may include said first and second pressure measuring units.

Packaging machine <NUM> may also comprise an analysis unit <NUM>, in particular operatively connected to pressure measuring device <NUM>, and configured to monitor the time-dependent course of pressure difference Δp (see the curve reproduced in solid lines in <FIG>). Preferably, the analysis unit <NUM> is the control unit which controls all the functionality of the packaging machine.

Analysis unit <NUM> is configured to determine a collapse of longitudinal seal portion <NUM>, in particular an opening and/or a losing of the integrity of longitudinal seal portion <NUM>, in dependence of the time-dependent course of pressure difference Δp.

Indeed, the Applicant has found that in the case of a collapse of longitudinal seal portion <NUM>, the measured pressure difference Δp may decrease, in particular significantly decrease (see <FIG> and the significant change of pressure difference Δp shown with solid line).

In particular, in the case of a collapse of longitudinal seal portion <NUM>, a fluidic connection between main chamber <NUM> and auxiliary chamber <NUM> occurs, which leads to first pressure p1 and second pressure p2 approaching one another. Additionally, pressure control device <NUM> cannot, at least immediately, compensate for the approaching first pressure p1 and second pressure p2.

According to some preferred non-limiting embodiments, analysis unit <NUM> may be configured to determine a collapse of longitudinal seal portion <NUM> if a drop of pressure difference Δp may be equal or exceed a threshold drop Δpthres. In particular, the drop of the pressure difference Δp may be calculated and/or defined as the difference between the desired and/or defined pressure difference value Δpdes and the measured pressure difference Δp.

In addition or alternatively, analysis unit <NUM> may be configured to determine a collapse of longitudinal seal portion <NUM> if the measured pressure difference Δp may equal or go below a lower limit value Δplow.

Preferentially but not necessarily, threshold drop Δpthres may be larger than or equal to <NUM> mbar, in particular <NUM> mbar, even more particular <NUM> mbar.

in the case that the desired and/or determined pressure difference value Δpdes may equal <NUM> mbar and the threshold drop Δpthres may defined as <NUM> mbar, analysis unit <NUM> may determine a collapse of longitudinal seal portion <NUM> if pressure difference Δp equals or is smaller than <NUM> mbar. According to such an example, the lower limit value Δplow may be <NUM> mbar.

The Applicant has found that the threshold drop Δpthres has to be chosen such to correctly determine a collapse without creating false alarms (i.e. erroneously identifying a collapse). This is preferentially guaranteed with threshold drop Δpthres may be larger than or equal to <NUM> mbar, in particular <NUM> mbar, even more particular <NUM> mbar.

According to some preferred non-limiting embodiments, threshold drop Δpthres may be smaller than or equal to <NUM> mbar, in particular <NUM> mbar, even more particular <NUM>,<NUM> mbar.

In particular, the definition of threshold drop Δpthres is chosen such to correctly detect a collapse of longitudinal seal portion <NUM> (without generating unwanted false alarms; i.e. without erroneously identifying a collapse).

According to some preferred non-limiting embodiments, analysis unit <NUM> may also be configured to signal the occurrence of a collapse of longitudinal seal portion <NUM> and/or to trigger an interruption of the production of packages <NUM> by means of packaging machine <NUM>, when, in use, analysis unit <NUM> has detected a collapse of longitudinal seal portion <NUM>.

According to some possible non-limiting embodiments, operation of tube forming and sealing device <NUM> may depend on the position of the sealing portion of web of packaging material <NUM> as determined by the at least one position sensor <NUM>.

Preferentially, the sensor device <NUM> may comprise at least two position sensors <NUM>, each one arranged upstream from isolation housing <NUM>, in particular also upstream from sterilization apparatus <NUM>, along web advancement path P.

Even more preferentially, at least one position sensor <NUM> may be arranged adjacent to the magazine unit (preferably at or downstream of the splicing device). Moreover or as an alternative, at least one position sensor <NUM> may be arranged adjacent to sterilization apparatus <NUM> (preferably upstream of the sterilization apparatus <NUM>).

Moreover, tube forming and sealing device <NUM> may be configured to modify operation, in particular modify an energy transfer, in dependence on whether the splicing portion advances within isolation housing <NUM>, in particular within main chamber <NUM> or not. In particular, the energy transfer needs to be larger when sealing tube <NUM> having the splicing portion.

The Applicant has observed that the occurrence of a collapse of longitudinal seal portion <NUM> may be more likely at the section of longitudinal seal portion <NUM> originating from the splicing portion, in comparison with the other section of longitudinal seal portion <NUM>.

According to some preferred non-limiting embodiments, analysis unit <NUM> may also be configured to determine a collapse of longitudinal seal portion <NUM> in dependence on whether, in particular during the drop of pressure difference Δp, the splicing portion advances within isolation housing <NUM> and/or while tube <NUM> having longitudinal seal portion <NUM> with the section originating from the splicing portion advances within isolation housing <NUM>. In particular, the analysis unit <NUM> is configured to activate the monitoring of the time-dependent course of the pressure difference Δp while the splicing portion advances within the isolation housing <NUM> and/or while the tube <NUM> having longitudinal seal portion <NUM> with the section originating from the splicing portion advances within isolation housing <NUM> and to deactivate the monitoring of the time-dependent course of the pressure difference Δp in other moments. In this way, it is possible to reduce false alarms. In fact, the occurrence of a collapse is more likely in the case of longitudinal seal portion <NUM> having the section originating from the splicing portion.

In another embodiment, the analysis unit <NUM> is configured to continuously monitor the time-dependent course of the pressure difference Δp, irrespectively of the position of the splicing portion.

With particular reference to <FIG> and <FIG>, filling device <NUM> may comprise a filling pipe <NUM> being at least partially placed within tube <NUM> for feeding the pourable product into tube <NUM>. In particular, filling pipe <NUM> may be in fluid connection with a pourable product storage tank.

According to some preferred non-limiting embodiments, filling device <NUM> may also comprise a filling level detection device configured to determine a filling level of the pourable food product within tube <NUM>. In particular, filling level detection device may comprise a floater configured to float on the pourable food product column present, in use, within tube <NUM> and a sensor (e.g. a magnetic sensor) configured read a relative position of the floater within the tube <NUM>.

Filling level detection device may be operatively connected to analysis unit <NUM> and analysis unit <NUM> may be configured to monitor the time-dependent course of the filling level (see the dashed curve in <FIG>).

Additionally, analysis unit <NUM> may be configured to detect a drop in the filling level, in particular a drop being larger or equal than a threshold value, and/or the filling level equaling or being smaller than a lower limit threshold filling level.

Moreover and according to some possible non-limiting embodiments, analysis unit <NUM> may be configured to detect a collapse of longitudinal seal portion <NUM> in dependence of the time-dependent course of the filling level, further to and/or instead of in dependence of the time-dependent course of pressure difference Δp.

In more detail, analysis unit <NUM> may be configured to detect a collapse of longitudinal seal portion <NUM> in dependence of the drop in the filling level and in dependence of the drop in pressure difference Δp and/or in dependence of the filling level equaling or going below the lower limit threshold filling level and the pressure difference Δp equaling or being smaller than lower limit value Δplow.

In particular, the drop in the filling level may be determined as the difference between a nominal filling level, which shall be maintained during production of packages <NUM>, and the measured filling level.

According to some possible non-limiting embodiments, analysis unit <NUM> may be configured to detect collapse of longitudinal seal portion <NUM> if the drop in the filling level equals or is larger than the threshold value and if the drop in pressure difference Δp equals or is larger than the pressure threshold value Δpthres.

According to some possible non-limiting embodiments the lower limit threshold filling level ranges between <NUM> and <NUM>, preferably between <NUM> and <NUM> of the nominal filling level.

In this manner, one reduces the risk of false alarms (i.e. of erroneously identifying a collapse).

According to some preferred non-limiting embodiments, analysis unit <NUM> may also be configured to determine a collapse of longitudinal seal portion <NUM>:.

With particular reference to <FIG> and <FIG>, sterilization station <NUM> may be arranged upstream of tube forming station <NUM> along web advancement path P. In other words, sterilization apparatus <NUM> may be arranged upstream of isolation housing <NUM> along path P. In even other words, in use, prior to web of packaging material <NUM> entering into isolation housing <NUM>, in particular main chamber <NUM>, web of packaging material <NUM> has been sterilized.

Preferentially, sterilization apparatus <NUM> may be arranged downstream of the magazine unit along web advancement path P.

In particular, package forming unit <NUM> may be arranged downstream of isolation housing <NUM> and tube forming and sealing device <NUM> along path Q.

In more detail, conveying device <NUM> may be adapted to advance tube <NUM> and any intermediate of tube <NUM> in a manner known as such along path Q, in particular from tube forming station <NUM> through a portion of main chamber <NUM> and to and through auxiliary chamber <NUM>, even more particular also towards and at least partially through package forming unit <NUM>.

In particular, with "intermediates of tube <NUM>" any configuration of web of packaging material <NUM> is meant prior to obtaining the tube structure and after folding of web of packaging material <NUM> by tube forming and sealing device <NUM> has started. In other words, the intermediates of tube <NUM> are a result of the gradual folding of web of packaging material <NUM> so as to obtain tube <NUM>, in particular by overlapping opposite lateral edges of web of packaging material <NUM> with one another.

With particular reference to <FIG>, sterilization apparatus <NUM> may configured to sterilize web of packaging material <NUM>, in particular the first face, even more particular also the second face, by means of physical sterilization such as by means of a sterilization irradiation, in particular an electromagnetic irradiation, even more particular by electron beam irradiation.

Alternatively or in addition, sterilization apparatus <NUM> could be configured to sterilize web of packaging material <NUM>, in particular the first face, even more particular also the second face, by means of chemical sterilization, in particular by means of hydrogen peroxide.

In more detail, according to the specific non-limiting example embodiment disclosed, sterilization apparatus <NUM> may comprise an irradiation device <NUM> arranged at sterilization station <NUM> and being adapted to sterilize at least the first face, preferentially also the second face, by directing a sterilizing irradiation, in particular electromagnetic irradiation, even more particular electron beam irradiation, onto at least the first face, preferentially also onto the second face, while, in use, web of packaging material <NUM> advances along a sterilization portion of path P; and.

More specifically, irradiation device <NUM> may comprise.

Preferably, electron beam emitter <NUM> and electron beam emitter <NUM> may be arranged side-by-side and distanced from one another so that at least a portion of advancement channel <NUM> is interposed between electron beam emitter <NUM> and electron beam emitter <NUM>.

With particular reference to <FIG> and <FIG>, isolation housing <NUM> is configured to separate an inner environment <NUM>, in particular having at least one sterile portion, from an outer environment <NUM>.

In more detail, main chamber <NUM> is the portion of isolation housing <NUM> in which web of packaging material <NUM> is, in use, formed into tube <NUM> and in which web of packaging material <NUM> is, in use, longitudinally sealed. In other words, main chamber <NUM> contains the portions of tube forming and sealing device <NUM>, which directly interact with web of packaging material <NUM> and tube <NUM> itself for forming and longitudinally sealing tube <NUM>.

In further detail, auxiliary chamber <NUM> may be arranged (directly) downstream of main chamber <NUM> along tube advancement path Q. In use, tube <NUM> advances through auxiliary chamber <NUM> after its formation and after its longitudinal sealing. In particular, in use, the formed and longitudinally sealed tube <NUM> advances directly from main chamber <NUM> into auxiliary chamber <NUM> (i.e. there is no further chamber arranged between main chamber <NUM> and auxiliary chamber <NUM>).

In particular, main chamber <NUM> and auxiliary chamber <NUM> may be connected, even more particular directly connected, to one another.

Preferentially, main chamber <NUM> may comprise a respective main inner space <NUM> defining a portion of inner environment <NUM>, in particular a sterile portion of inner environment <NUM>. In other words, main chamber <NUM> may be preferentially an aseptic main chamber <NUM> (i.e. main chamber <NUM> may be kept aseptic during production).

In even other words, in use, web of packaging material <NUM> may advance through a portion of main chamber <NUM> prior to being formed into tube <NUM>. As preferentially inner space <NUM> may be sterile, sterility of web of packaging material <NUM> and of tube <NUM> is maintained.

Preferentially, auxiliary chamber <NUM> may comprise an auxiliary inner space <NUM> defining a further portion of inner environment <NUM>. Auxiliary inner space <NUM> may be an environment not sterile.

Preferentially, isolation housing <NUM> may also comprise a containment chamber <NUM> arranged downstream of auxiliary chamber <NUM> along tube advancement path Q and being configured to receive gas (present within auxiliary chamber <NUM> itself and) leaking from auxiliary chamber <NUM>.

In particular, containment chamber <NUM> may be connected to, in particular directly connected to, auxiliary chamber <NUM>. In other words, in use, tube <NUM> may advance from auxiliary chamber <NUM> into containment chamber <NUM>.

In the preferred non-limiting embodiment shown, isolation housing <NUM> may comprise an inlet portion <NUM> for receiving web of packaging material <NUM> and an outlet portion <NUM> for allowing discharging of tube <NUM> from isolation housing <NUM> itself, in particular into package forming unit <NUM>.

Preferentially, main chamber <NUM> may comprise inlet portion <NUM>.

Preferably, containment chamber <NUM> may define and/or comprise outlet portion <NUM>.

In the preferred non-limiting embodiment shown, sterilization apparatus <NUM> may be coupled to, in particular connected to, main chamber <NUM>, in particular so that web of packaging material <NUM> advances from sterilization apparatus <NUM> into main chamber <NUM>.

Preferably, isolation housing <NUM> may also comprise at least one main separation wall for separating main chamber <NUM> and auxiliary chamber <NUM> from one another.

In particular, the portions of tube forming and sealing device <NUM>, which may be arranged within main chamber <NUM>, may be positioned upstream of main separation wall along tube advancement path Q.

With particular reference to <FIG>, package forming unit <NUM> may comprise a plurality of complementary pairs of operative units <NUM> (only schematically shown) configured to at least shape and transversally seal, in particular also to transversally cut, packages <NUM>.

More specifically and with particular reference to <FIG>, pressure control device <NUM> may comprise:.

Even more specifically, gas conditioning unit <NUM> may comprise an injection tube <NUM> at least partially arranged within main chamber <NUM> and configured to inject the (sterile) gas into main chamber <NUM> and, preferably also a control valve <NUM> for controlling the flow of gas within injection tube <NUM>.

More specifically, injection tube <NUM> may extend at least partially within main chamber <NUM> parallel to axis A and comprises a plurality of nozzles for injecting the pressurized gas into main chamber <NUM>.

Additionally, gas conditioning unit <NUM> may be further configured to at least pressurize the gas, even more preferentially to pressurize and sterilize the gas, in particular at least prior to its injection into main chamber <NUM>.

Moreover, gas conditioning unit <NUM> may also comprise a further injection tube <NUM> configured to inject the pressurized (sterile) gas into sterilization apparatus <NUM>, in particular into shielding chamber <NUM>. Preferentially, injection tube <NUM> may be configured to inject the gas at an interface between sterilization apparatus <NUM> and isolation housing <NUM>.

Preferentially, pressure control device <NUM> may also comprise a control valve <NUM>, preferably a ball valve, arranged within flow conduct <NUM> and being configured to control the flow of gas from main chamber <NUM> to auxiliary chamber <NUM> through flow conduct <NUM>, in particular for controlling the second pressure. In particular, the control valve <NUM> of the control device <NUM>, regulating the flow of gas through the flow conduct <NUM>, controls the pressure difference Δp between first pressure p1 and second pressure p2 (Δp = p1 - p2).

The pressure measuring device <NUM> comprises the first measuring unit <NUM> configured to measure and/or determine first pressure p1. Preferably, the pressure control device <NUM> may be configured to control the control valve <NUM> as a function of the first pressure as measured and/or determined by the first measuring unit <NUM>.

In a preferred non-limiting embodiment, a pressure within the containment chamber <NUM> may be about the ambient pressure. It is to be noted that gas being present in auxiliary chamber <NUM> may also (in a non-controlled manner) leak into containment chamber <NUM>.

In a preferred non-limiting embodiment, pressure control device <NUM>, in particular gas conditioning unit <NUM>, may configured to aspirate gas from sterilization apparatus <NUM>, in particular shielding chamber <NUM>, and to direct it to gas conditioning unit <NUM> itself, in particular for purposes of recirculation.

With particular reference to <FIG>, tube forming and sealing device <NUM> may comprise at least a tube forming group <NUM> configured to form tube <NUM> from the, in use, advancing web of packaging material <NUM> and at least a sealing head <NUM> configured to longitudinally seal tube <NUM>.

More specifically, tube forming group <NUM> and sealing head <NUM> may be arranged within main chamber <NUM>.

In more detail, tube forming group <NUM> may comprise at least a plurality of forming ring assemblies <NUM>, in the particular example shown in <FIG> two forming ring assemblies <NUM>, arranged within main chamber <NUM> and being configured to fold web of packaging material <NUM> gradually into tube <NUM>, in particular by overlapping the respective lateral edges of web of packaging material <NUM>.

In particular, forming ring assemblies <NUM> may arranged within parallel and spaced apart planes, in particular being orthogonal to axis A, even more specifically having a substantially horizontal orientation. Preferably, the forming ring assembly <NUM> being arranged downstream of the other one may be designed to also exert a mechanical force on tube <NUM>, in particular for promoting the longitudinal sealing of tube <NUM>.

In use, packaging machine <NUM> forms packages <NUM> filled with the pourable product.

In more detail, a method of forming packages <NUM> comprises the following steps:.

In more detail, during the step of controlling, pressure difference Δp is maintained at a desired and/or defined pressure difference value Δpdes, in particular under normal operation conditions.

Preferentially, the pressure difference Δp fluctuates around the desired and/or defined pressure difference value Δpdes.

Furthermore, during the step of controlling, pressure control device <NUM> may control pressure difference Δp, in particular by controlling first pressure p1 and second pressure p2.

More specifically, during the step of determining, the collapse of the longitudinal seal portion <NUM> may be determined if a drop of pressure difference Δp equals or exceeds a threshold drop Δpthres and/or if the measured pressure difference Δp equals or is lower than a lower limit value Δplow.

In particular, the step of determining and the step of monitoring may be executed by analysis unit <NUM>.

The method of forming packages <NUM> may further comprise the steps of:.

Additionally, during the step of determining, the collapse of longitudinal seal portion <NUM> may be also determined in dependence of the time-dependent course of the filling level.

In particular, the collapse of longitudinal seal portion <NUM> may also be determined in dependence of a measured drop in the filling level, in particular being larger than a determined filling level drop.

Additionally or in alternative, the collapse of longitudinal seal portion <NUM> may also be determined if the filling level equals or is smaller than a lower limit threshold filling level.

By combining the criteria related to the pressure difference Δp and the one related to the filling level, it is possible to reduce a risk of erroneously determining a collapse of longitudinal seal portion <NUM>.

In further detail, during the step of detecting, the relative position of the floater is detected (in order to measure the filling level).

The method of forming packages <NUM> may also comprise a step of splicing, during which the web of packaging material <NUM> in use is spliced with the new web of packaging material <NUM>. In particular, during the step of splicing, the trailing portion of the web of packaging material <NUM> in use is spliced together with the leading portion of the new web of packaging material.

Moreover, during the step of splicing one obtains web of packaging material <NUM> having the spliced portion.

Advantageously, during the step of determining, a collapse of longitudinal seal portion <NUM> is determined also in dependence on whether, in use, the splicing portion advances within isolation housing <NUM> and/or a section of the longitudinal seal portion <NUM> originating from the splicing portion advances within the isolation housing <NUM>.

By combining this criterion together with at least the criterion related to difference pressure Δp one decreases the risk of erroneously detecting a collapse of longitudinal seal portion <NUM>. Additionally, for detecting the longitudinal seal portion <NUM>, one may also consider the criterion related to the filling level.

According to some possible non-limiting embodiments, during the step of determining, a collapse of longitudinal seal portion <NUM> may be determined:.

The method of forming packages <NUM> may also comprise a step of detecting the position of the splicing portion along the web advancement path P by means of the sensor device, in particular the one or more position sensors <NUM>. Moreover, on whether the splicing portion and/or the section of the longitudinal seal portion <NUM> originating from the splicing portion may advance within isolation housing <NUM> may be determined from knowing the relative position and operation of conveying device <NUM>.

The method of forming packages <NUM> may also comprise a step of signaling, during which the occurrence of a collapse of the longitudinal seal portion <NUM> is signaled. In this way, it is possible to alert an operator e.g. such that the operator can decide to interrupt the formation of packages <NUM>.

Alternatively or in addition, the method of forming packages <NUM> may also comprise a step of triggering, during which an interruption of the formation of packages <NUM> is interrupted if during the step of determining, a collapse of the longitudinal seal portion <NUM> is determined.

In a preferred non-limiting embodiment, the method also comprises the step of sterilizing at least the first face, in particular also the second face, of web of packaging material <NUM> at sterilization station <NUM>. In particular, the step of sterilizing is executed before the step of folding web of packaging material <NUM>. Even more particularly, the step of sterilizing is executed prior to web of packaging material entering into isolation housing <NUM>.

During the step of folding tube <NUM>, tube forming and sealing device <NUM> gradually overlaps the opposite lateral edges of web of packaging material <NUM> with one another so as to form a longitudinal seal.

During the step of longitudinally sealing tube <NUM>, tube forming and sealing device <NUM> seals the overlapped opposite lateral edges of web of packaging material <NUM> to obtain the longitudinal seal.

During the step of advancing tube <NUM>, conveying device <NUM> advances tube <NUM> (and any intermediates of tube <NUM>) along path Q to package forming unit <NUM>.

In particular, conveying device <NUM> advances tube <NUM> through a portion of main chamber <NUM>, to and through auxiliary chamber <NUM>, and preferably to and through containment chamber <NUM>.

During the step of filling tube <NUM>, filling device <NUM> fills the pourable product into the longitudinally sealed tube <NUM>.

During the step of obtaining single packages <NUM>, package forming unit <NUM> forms and transversally seals tube <NUM> between successive packages <NUM> and, preferentially, also transversally cuts tube <NUM> between successive packages <NUM>.

In more detail, during the step of sterilizing web of packaging material <NUM>, at least a sub-step of directing a sterilizing irradiation, in particular electromagnetic irradiation, even more particular electron beam irradiation, onto at least the first face, preferentially also onto the second face, of web of packaging material <NUM> is executed.

The advantages of packaging machine <NUM> and/or the method according to the present invention will be clear from the foregoing description.

In particular, it is possible to determine in a timely manner the occurrence of a collapse of the longitudinal seal portion <NUM>. This again allows to take the needed actions in a timely manner.

Claim 1:
A packaging machine (<NUM>) for producing packages (<NUM>) of a pourable product from a web of packaging material (<NUM>) advancing along a web advancement path (P), the packaging machine (<NUM>) comprises:
- a conveying device (<NUM>) for advancing the web of packaging material (<NUM>) along the web advancement path (P) to a tube forming station (<NUM>) at which the web of packaging material (<NUM>) is formed, in use, into a tube (<NUM>) and for advancing the tube (<NUM>) along a tube advancement path (Q);
- an isolation housing (<NUM>) having a main chamber (<NUM>) and an auxiliary chamber (<NUM>) arranged downstream form the main chamber (<NUM>) along the tube advancement path (Q) ;
- a tube forming and sealing device (<NUM>) at least partially arranged within the main chamber (<NUM>) and being configured to form and longitudinally seal the tube (<NUM>), in use, within the main chamber (<NUM>), the tube (<NUM>) having a longitudinal seal portion (<NUM>);
- a filling device (<NUM>) for filling the tube (<NUM>) with the pourable product;
- a pressure control device (<NUM>) configured to control a first pressure (p1) within the main chamber (<NUM>) and a second pressure (p2) within the auxiliary chamber (<NUM>), the second pressure (p2) being different from the first pressure (p1);
- a pressure measuring device (<NUM>) configured to measure a pressure difference (Δp) between the first pressure (p1) and the second pressure (p2); and
- an analysis unit (<NUM>) operatively connected to the pressure measuring device (<NUM>) and configured to monitor a time-dependent course of the pressure difference (Δp);
wherein the analysis unit (<NUM>) is configured to determine a collapse of the longitudinal seal portion (<NUM>) in dependence of the time-dependent course of the pressure difference (Δp).