Sterilization device, packaging machine having sterilization device, and sterilization method

Abstract

A sterilization apparatus (9) is described for sterilizing a web (4) of packaging material advancing along a web advancement path (P). The sterilization apparatus (9) comprises: - a first sterilization device (10) configured to sterilize at least a first surface (5) of a web (4) passing through the first sterilization device (10); - a second sterilization device (7), a monitoring device (8) configured to monitor the operation of the first sterilization device (10); a movement sensor (11) configured to monitor the advancement of the web (4) along an advancement path (P); a control unit (12) connected to the monitoring device (8) and the movement sensor (11), the control unit (12) being configured to: - blocking the advance of the web (4), - determining the distance (D) travelled by the web (4) between the detection of the anomaly and the interruption of its advance, - sterilizing at least a portion (P1, P2, P3) of the web (4) by means of a second sterilization device (7), the portion (P1, P2, P3) of the web being related to the distance traveled (D).

Description

[Technical Field]

[0001] The present invention relates to a sterilization apparatus for sterilizing a web of packaging material, in particular a web of packaging material for producing sealed packages of pourable products, in particular pourable food products.

[0002] The invention also relates to a packaging machine for producing sealed packages of pourable products, in particular pourable food products, having a sterilization device.

[0003] The present invention also relates to a method for sterilizing a web of packaging material, in particular a method for sterilizing a web of packaging material for producing sealed packages of pourable products, in particular pourable food products. [Background technology]

[0004] As is well known, many liquid or pourable food products, such as fruit juice, UHT (ultra-high temperature processed) milk, wine, tomato sauce, etc., are sold in packages made from sterilized packaging material.

[0005] A typical example is the parallelepiped package for liquid or pourable food products known as Tetra Brik Aseptic®, which is made by sealing and folding a laminated strip of packaging material. This packaging material has a multi-layer structure, for example, a base layer of paper covered on both sides with layers of heat-sealable plastic, for example, polyethylene. In the case of aseptic packages for long-life products such as UHT milk, the packaging material includes a layer of oxygen barrier material (oxygen barrier layer), for example, aluminum foil, which is laminated with a layer of heat-sealable plastic material and covered with another layer of heat-sealable plastic material that ultimately forms the inner surface of the package that comes into contact with the food.

[0006] This type of package is typically produced by a fully automatic packaging machine that advances the web of packaging material from a magazine unit, through a sterilization device for sterilizing the web of packaging material, and into an isolation chamber (a closed, sterile environment) in which the sterilized web of packaging material is maintained and advanced. As the web of packaging material advances through the isolation chamber, it is folded and sealed longitudinally to form a tube with a longitudinal seam, which tube is further fed along a vertical advance direction.

[0007] To complete the forming operation, the tube is filled with a sterilized or aseptically processed pourable product, in particular a pourable food product, sealed transversely, and then cut along equally spaced transverse cross sections in the package forming unit of the packaging machine while advancing along a vertical direction.

[0008] Each pillow package is thus obtained in the packaging machine, each pillow package having a longitudinal seal band, an upper transverse seal band and a lower transverse seal band.

[0009] In recent years, sterilization devices have become available that are configured to sterilize webs of packaging material by application of physical radiation, particularly electromagnetic radiation, and more particularly electron beam radiation. Sterilization devices that utilize hydrogen peroxide are also known, in which the web of packaging material is sterilized by introducing it into a hydrogen peroxide bath. Summary of the Invention [Problem to be solved by the invention]

[0010] Although known sterilizers and packaging machines have provided satisfactory results, there is a perceived need to improve the performance of sterilizers.

[0011] For example, there is a felt need to efficiently and timely address anomalies in the operation of sterilizers, such as temperature anomalies in the peroxide bath in the case of hydrogen peroxide sterilization, ultraviolet lamp radiation anomalies and / or arcing events in the case of e-beer sterilization.

[0012] Such anomalies can cause temporary interruptions in production, sometimes lasting up to several hours, resulting in economic losses and time-consuming work for machine operators. Therefore, there is a need to provide solutions that minimize machine downtime. There is also a need to promote downtime minimization while improving sterilization performance.

[0013] For example, with electron beam emitters, if an electric arc occurs, the packaging machine must be shut down. An operator then manually cuts off the bottom of the packaging material, connects a cleaning pipe to clean the filling means, cleans the sterilizer, and replaces the packaging material in the correct position. A further sterilization step is then performed before normal packaging operation can resume. This process is time-consuming, and downtime can last for several hours. [Means for solving the problem]

[0014] It is therefore an object of the present invention to provide a sterilization device that facilitates overcoming at least one of the aforementioned drawbacks in a simple and cost-effective manner.

[0015] In particular, it is an object of the present invention to provide a sterilization apparatus that can respond to operational anomalies in a time-efficient manner.

[0016] It is a further object of the present invention to provide a packaging machine which facilitates overcoming at least one of the aforementioned drawbacks in a simple and low-cost manner.It is a further object of the present invention to provide a sterilization method which overcomes at least one of the aforementioned drawbacks in a simple and low-cost manner.

[0017] According to the present invention, there is provided a sterilization apparatus as set forth in claim 1.

[0018] According to the present invention, there is provided a packaging machine as set forth in claim 12.

[0019] According to the present invention, there is provided a sterilization method as set forth in claim 15.

[0020] Preferred embodiments are set forth in the dependent claims.

[0021] Non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of a packaging machine with a sterilizer according to one or more embodiments, with parts removed for clarity. [Figure 2] FIG. 1 is a schematic diagram of a sterilization apparatus with parts removed for clarity, according to one or more embodiments. [Figure 3] FIG. 10 is a schematic diagram of the sterilization device 9 when an abnormality is detected and after the advance of the web is interrupted. [Figure 4] FIG. 10 is a schematic diagram of the sterilization device 9 when an abnormality is detected and after the advance of the web is interrupted. DETAILED DESCRIPTION OF THE INVENTION

[0023] Number 1 indicates generally a packaging machine for producing sealed packages 2 of pourable products, in particular pourable food products such as pasteurised milk, fruit juice, wine, tomato sauce, etc., from a tube 3 formed from a web 4 of packaging material. In particular, in use, the tube 3 extends along a longitudinal direction, in particular vertically.

[0024] The web 4 comprises at least a layer of fibrous material, in particular paper, covered on both sides with respective layers of heat-sealable plastic material, for example polyethylene.

[0025] Preferably, web 4 comprises a layer of gas and light barrier material, such as aluminum foil or ethylene vinyl alcohol (EVOH) film, and at least first and second layers of heat-sealable plastic material. The layer of gas and light barrier material is laminated with a first layer of heat-sealable plastic material and covered with a second layer of heat-sealable plastic material. The second layer of heat-sealable plastic material ultimately forms the inner surface of package 2 that contacts the filled pourable food product.

[0026] More specifically, web 4 has a first side or surface 5 and a second side or surface 6, and in particular first (front) surface 5 is the side of web 4 that forms the inner surface of the formed package 2 that ultimately contacts the filled pourable food product.

[0027] A typical package 2 obtained by the packaging machine 1 comprises a longitudinal sealing band and a pair of transverse sealing bands, in particular an upper transverse sealing band and a lower transverse sealing band.

[0028] With particular reference to FIG. 1 , packaging machine 1 is configured to advance web 4 along web advancement path P, sterilize web 4 while advancing along path P, form tube 3 from web 4, fill tube 3, and form single package 2 from filled tube 3.

[0029] Preferably, the packaging machine 1 comprises: a sterilization device 9 including a first sterilization device 10 adapted to sterilize at least a first (surface) 5, and in particular a second (surface) 6, of the web 4; an isolation chamber 14 separating an internal environment 15, in particular an internal sterile environment, from an external environment 16; a tube forming device 17 at least partially, preferably completely, disposed within the isolation chamber 14 and configured, in use, to advance and form a tube 3 from the sterilized web 4; a sealing device 19 disposed at least partially within the isolation chamber 14 and configured to longitudinally seal the tube 3 formed by the tube forming device 17 so as to form a longitudinal seam portion of the tube 3; a filling unit 20 adapted to fill the tube 3 with a pourable product, in particular a pourable food product; - a package forming unit 21 adapted to at least form and transversely seal a tube 3 for forming a package 2, in particular a tube 3 that advances in use; - a plurality of conveyors configured to advance the web 4 along a path P in a known manner and to advance the tube 3 along a tube advance path Q; Equipped with.

[0030] In particular, the sterilizer 9 may receive a web 4 of packaging material from a host station (not shown).

[0031] For example, multiple conveyors may be configured to advance the web of packaging material 4 from the host station to the sterilizer 9 and / or from the sterilizer 9 to the tube forming machine 17. For example, multiple conveyors may be configured to advance the tube 3 from the tube forming machine 17 to the sealing machine 19 and / or from the sealing machine 19 to the filling machine 20 and / or from the filling machine 20 to the package forming machine 21.

[0032] Preferably, the plurality of conveyors are adapted to advance the tubes 3 and any intermediate portions of the tubes 3 along path Q, in particular from the tube forming equipment 17 towards and at least partially through the package forming device 21, in a known manner.

[0033] In one or more embodiments, the plurality of conveyors comprises a first conveyor 22 upstream of the sterilizer 9. In particular, the first conveyor 22 may be positioned immediately upstream of the entrance 90 of the sterilizer 9.

[0034] Preferably, the packaging machine 1 also comprises pressure control means arranged to control the pressure in at least the isolation chamber 14 and in at least part of the sterilizer 9 .

[0035] The sterilizer 9 may be located upstream of the tube forming station 17 relative to the web advance path P.

[0036] The sterilization apparatus 9 may include an outlet 92. The outlet 92 may be located downstream relative to the first sterilization instrument 10 along the web advancement path P, and the sterilized web 4 may advance through the outlet 92 toward the isolation chamber 14.

[0037] The isolation chamber 14 may include an inlet 140 , which may be connected to the outlet 92 of the sterilization device 9 .

[0038] The isolation chamber 14 may include an outlet 142 at which the tube 3 filled with pourable product may exit the isolation chamber 14 .

[0039] The package forming apparatus 21 may be located along path Q downstream of the isolation chamber 14 and the tube forming equipment 17 .

[0040] As shown with particular reference to Figures 3 and 4, in one or more embodiments, the sterilization device 9 is configured as follows: a first sterilization device 10 configured to sterilize at least a first (surface) 5, preferably a second (surface) 6, of a web 4 passing through the first sterilization device 10; - a second sterilization device 7; a monitoring device 8 configured to monitor the operation of the first sterilization device 10; a movement sensor 11 configured to monitor the advancement of the web 4 along the advancement path P; a control unit 12 connected to the monitoring device 8 and the movement sensor 11, the control unit 12 being adapted to: - impeding the progress of Web 4, - determining the distance D traveled by the web 4 from the detection of the anomaly until the interruption of its advance, - sterilizing at least a portion P1, P2, P3 of the web 4 by means of a second sterilization device 7, the portion P1, P2, P3 being related to (e.g. substantially corresponding to) the travel distance D.

[0041] The first sterilization equipment 10 may comprise an irradiation device configured to sterilize at least the first surface 5, preferably the second surface 6, of the advancing web 4 by applying sterilizing radiation to at least the first surface 5 (and optionally the second surface 6).

[0042] A typical sterilizer of this type will typically include an irradiation device having a pair of spaced apart electron beam emitters, with an advance channel interposed between the electron beam emitters through which a web of packaging material 4 advances in use, and each electron beam emitter configured to apply a respective electron beam to one side of the web of packaging material advancing through the advance channel.

[0043] A drawback of this type of sterilization apparatus 10 is the possibility of electrical arcing. During operation of the electron beam emitter, electrical discharges, i.e., electrical arcing, can occur that can change the dose of radiation directed to surface 5 and / or surface 6. That is, an anomaly can include an electrical arcing event. Control unit 12 may be configured to detect whether a change occurs in the dose of radiation directed to first surface 5 (and optionally second surface 6) of web 4.

[0044] In the accompanying figures, the first sterilization equipment 10 is depicted as an irradiator, as previously described, but it will be appreciated that a different type of first sterilization equipment 10 may be employed, for example a hydrogen peroxide bath, in which case the abnormality may comprise, for example, a change in temperature of the hydrogen peroxide bath.

[0045] In the event of an abnormality in the operation of the first sterilisation equipment 10, the control unit 12 may be configured to interrupt the operation of the packaging machine 1. In particular, the control unit 12 may interrupt the operation of the first sterilisation equipment 10, the tube forming equipment 17, the sealing device 19, the filling device 20, the package forming device 21 and / or several conveyors, preferably simultaneously.

[0046] According to one or more embodiments, the travel distance D is less than the distance D1 between the first sterilization instrument 10 and the outlet 92. That is, the travel distance D may be less than the distance D1 that the web 4 travels between the first sterilization instrument 10 and the outlet 92 during normal operation.

[0047] For example, portions P1, P2, P3 associated with (e.g., substantially corresponding to) travel distance D may comprise portions of web 4 in (e.g., passing through) first sterilization instrument 10 between the detection of the anomaly and the interruption of advancement. For example, portions P1, P2, P3 may comprise a first portion P1-P2 that exits first sterilization instrument 10 between the detection of the anomaly and the interruption of advancement, and a second portion P2-P3 that is present in (e.g., within) first sterilization instrument 10 when advancement of the web is interrupted.

[0048] Thus, the step of sterilizing at least portions P1, P2, P3 associated with the travel distance D may comprise sterilizing at least a first portion P1-P2 substantially corresponding to the distance D and / or sterilizing a second portion P2-P3 in the first sterilization equipment 10 during an interruption in the advancement of the web.

[0049] Advantageously, the advancement of the web 4 may be interrupted before the first portion P1-P2 of the web 4 reaches the outlet 92 of the sterilizer 9. In this way, the first portion P1-P2 does not enter the isolation chamber 14.

[0050] Advantageously, the control unit 12 may therefore be configured to identify (accurately and efficiently) the portions P1, P2, P3 passing through the first sterilisation equipment 10 when a deviation from its normal operation is detected. In this way, it is possible to identify (accurately and accurately) the portions P1, P2, P3 of the web 4 of packaging material that may be affected by the anomaly.

[0051] For example, the movement sensor 11 may transmit a first sensor signal indicative of, for example, the speed and / or position and / or distance traveled of the web of packaging material 4 .

[0052] Advantageously, the web 4 and tube 3 of packaging material present in the isolation chamber 14 and sterilization device 9 at the time of detection of the abnormality may be present (i.e. remain) in the packaging machine 1 before, during and after sterilization by the second sterilization equipment 7.

[0053] Advantageously, by identifying the travel distance D and / or the portions P1, P2, P3 affected by an anomaly, downtime due to such an anomaly can be significantly reduced, and sterilization is localized to the affected portion and optionally adjacent portions.

[0054] FIG. 3 shows the sterilization device 9 according to one or more embodiments when an abnormality occurs.

[0055] The control unit 12 may be configured to receive a second sensor signal from the monitoring device 8, for example indicative of sterilization of the web 4 of packaging material.

[0056] The control unit 12 may be configured to detect the anomaly when the second sensor signal reaches (and optionally exceeds) a predetermined threshold. For example, if the monitoring equipment includes an irradiation sensor, the second sensor signal may indicate the irradiation dose emitted by the first sterilization equipment 10. The control unit 12 may be configured to detect the anomaly when the emitted dose of radiation reaches (e.g., becomes low) a threshold, for example, a low dose value of radiation.

[0057] Preferably, the control unit 12 may be configured to detect an anomaly when the second sensor signal reaches (or exceeds) a predetermined threshold for a predetermined time. The predetermined time may be between 50 ms and 120 ms, preferably between 70 ms and 110 ms, and more preferably between 80 ms and 100 ms. The predetermined time may depend on the advancement speed of the web 4 of packaging material. For example, the predetermined time may be indirectly proportional to the advancement speed, i.e., the lower the advancement speed, the longer the predetermined time.

[0058] More preferably, the control unit 12 may be configured to detect an anomaly when the second sensor signal reaches (or exceeds) a predetermined threshold value for a predetermined period of time, i.e., the second sensor signal reaches (or exceeds) the threshold value over the entire predetermined time period. Advantageously, the predetermined period of time makes it easier to detect real anomalies and filter out false anomalies, e.g., fluctuations in the sensor signal due to electrical disturbances.

[0059] The control unit 12 may be configured to begin determining (e.g., calculating) the distance D at the beginning of the predetermined time period. The control unit 12 may be configured to interrupt the advancement of the web 4 at the end of the predetermined time period.

[0060] Figure 4 shows the sterilisation device 9 according to one or more embodiments when operation of the sterilisation device 9 (and packaging machine 1) is interrupted. The first portion P1-P2 may correspond (substantially) to the travel distance D, and the second portion P2-P3 may comprise the portion of the first sterilisation equipment 10 that is present (e.g. present within) it while advancement is interrupted.

[0061] In one or more embodiments, the second sterilization equipment 7 may include a hydrogen peroxide spray tank 70 configured to spray vaporized hydrogen peroxide onto at least the portions P1, P2, and P3 of the web 4 associated with the travel distance D from the detection of the anomaly to the interruption.

[0062] As shown, the spray tank 70 may be connected to a tube 72 configured to deliver vaporized hydrogen peroxide at its outlet to the first sterilization device 10, and in particular to the web advancement path P.

[0063] Spray tank 70 may be configured to sterilize portions P1-P3 of web 4 via tube 72. Air (e.g., gas stream) exiting tube 72 passes through first sterilization equipment 10 and may be collected through tube 74 (only a portion of which is shown). Such air may flow through first sterilization equipment in a direction counter to the direction of advancement of the web along web advance path P.

[0064] The second sterilization device 7 may be configured to sterilize portions P1, P2, P3 of the web 4, similar to the first sterilization device 10 and / or sterilization device 9 generally.

[0065] As a preferred additional precaution, the second sterilization device 7 may be configured to sterilize the isolation chamber 14 .

[0066] The spray tank 70 may be connected to a further tube 76 configured to carry the vaporized hydrogen peroxide in the isolation chamber 14 , and in particular the tube 76 may terminate downstream relative to the tube forming device 17 .

[0067] The spray tank 70 may be configured to sterilize the isolation chamber 14 by means of a further tube 76. Air (e.g., gas flow) exiting the further tube 76 may pass through the isolation chamber 14, the first sterilization device 10, and be collected through the tube 74.

[0068] In other words, when the advancement of the web is interrupted, the second sterilisation equipment 7 may be configured to spray sterile air containing hydrogen peroxide onto the first sterilisation equipment 10, preferably via the isolation chamber 14.

[0069] The second sterilization device 7 can only be activated if the advancement of the web is interrupted and / or the first sterilization device 10 is deactivated.

[0070] According to one or more embodiments, the movement sensor 11 may comprise, for example, a rotary encoder integrated into one of a plurality of conveyors configured to advance the web 4, preferably the conveyor upstream of the sterilizer 9. Preferably, the first conveyor 22 may comprise the movement sensor 11, although any conveyor upstream of the sterilizer 9 may comprise the movement sensor 11.

[0071] The conveyor constituting the movement sensor 11 may not be subject to an actuating force. In other words, the conveyor may have free rollers that rotate only due to the movement of the web 4. No external force is applied to such a conveyor to influence its rotation. Thus, in an embodiment, when the web 4 moves forward, the first conveyor 22 rotates in a first direction, e.g., counterclockwise in the figure, and when the web 4 moves backward, the first conveyor 22 rotates in a second direction opposite to the first direction, e.g., clockwise.

[0072] Advantageously, this allows for a more accurate reading of the distance D, insofar as possible backward movement of the web 4 of packaging material is also taken into account.

[0073] The second conveyor may contact the web 4 on the conveyor with the movement sensor 11 on the opposite side of the web 4 to the conveyor with the movement sensor 11. In this way, the web 4 of packaging material does not slip on the conveyor and a more accurate reading is obtained.

[0074] According to one or more embodiments, for example, one or more conveyors (immediately) upstream of the sterilizer 9 may be equipped with an actuator configured to control the braking speed of the advancing web 4. Advantageously, in this way, the travel distance D of the web 4 before interruption may be reduced.

[0075] Additionally or alternatively, the actuator may be configured to control the tension in the advancing web 4. Advantageously, in this way, the web 4 of packaging material remains in tension even when the packaging machine 1 is stopped, facilitating sterilization and reducing the risk of damage to the web 4.

[0076] In one or more embodiments, the first conveyor 22 may be equipped with a movement sensor 11 and an actuator. Additionally or alternatively, a further conveyor, such as one immediately upstream of the first conveyor 22, may be equipped with an actuator.

[0077] The control unit 12 may be configured to resume the advancement of the web of packaging material 4 after the sterilization step is completed by the second sterilization equipment 7. That is, the web of packaging material 4 remains within the packaging machine 1 before, during and after the abnormality is detected.

[0078] At least during the step of sterilization by the second sterilization equipment 7, the package 2 formed of the packaging material present in the sterilization device 9 and isolation chamber 14 may be discarded.

[0079] Further, according to one embodiment, the control unit 12 may be configured to, for example, send a warning signal to a user interface if the travel distance D is greater than a predetermined distance, for example the distance D1 between the first sterilization instrument 10 and the outlet 92 of the sterilization apparatus 9. A cleaning and resterilization process is then performed on the isolation chamber 14, the filling unit 20 and the sterilization apparatus 9.

[0080] One or more embodiments may relate to a method of sterilizing a web 4 of packaging material performed by a sterilization apparatus 9 according to one or more embodiments. The method includes: - advancing a web 4 of packaging material along a web advancement path P; - sterilizing at least a first surface 5 and preferably a second surface 6 of the advancing web 4 by means of a first sterilization device 10; - monitoring the operation of the first sterilization device 10; - monitoring the advancement of the web 4 along the advance path P; Equipped with - if an abnormality is detected in the operation of the first sterilization device 10: - impeding the progress of Web 4, - determining the distance D travelled by the web 4 from the detection of the anomaly until the advance is interrupted, - sterilizing at least a portion P1, P2, P3 of the web 4 by means of a second sterilization device 7, the portion P1, P2, P3 of the web being associated with a distance D traveled.

[0081] The advantages of the sterilization device 9 according to the invention will be clear from the above description. In particular, the sterilization device 9 can minimize the downtime of the packaging machine 1 compared to those known in the art. More particularly, the downtime can be reduced from several hours to a few tens of minutes.

[0082] However, it will be apparent that modifications may be made to the sterilisation device 9 described herein without departing from the scope of protection defined in the appended claims.

Claims

1. A sterilization device (9) for sterilizing a web (4) of packaging material advancing along an advancing path (P), said sterilization device (9) comprising: a first sterilization device (10) configured to sterilize at least a first surface (5) of a web (4) passing through the first sterilization device (10); a second sterilization device (7); a monitoring device (8) configured to monitor the operation of the first sterilization device (10); a movement sensor (11) configured to monitor the advancement of said web (4) along said advancement path (P); a control unit (12) connected to the monitoring device (8) and the movement sensor (11); and when an abnormality is detected in the operation of the first sterilization equipment (10), the control unit (12) blocking the advancement of said web (4); and determining a distance (D) traveled by the web (4) from the time an abnormality is detected until advancement is interrupted, wherein the second sterilization device (7) sterilizes at least a portion (P1, P2, P3) of the web (4), the portion (P1, P2, P3) of the web being associated with the distance (D); Sterilizer (9).

2. the sterilization device (9) has an outlet (92), and the traveled distance (D) is smaller than the distance (D1) between the first sterilization equipment (10) and the outlet (92); A sterilization device (9) according to claim 1.

3. The step of detecting an abnormality in the operation of the first sterilization equipment (10) comprises: receiving a sensor signal from said monitoring device (8); checking whether said sensor signal reaches a predetermined threshold value for a predetermined time, preferably continuously; Including, A sterilization device (9) according to claim 1 or 2.

4. the first sterilization equipment (10) comprises an irradiation device configured to sterilize the first surface (5) of the advancing web (4) by applying sterilizing radiation to the first surface (5), and the anomaly is an electric arc event; A sterilization device (9) according to any one of claims 1 to 3.

5. the monitoring device (8) comprises an irradiation sensor configured to detect a dose of radiation emitted by the first sterilization device (10), and the control unit (12) is configured to detect an abnormality when the dose of radiation emitted reaches a predetermined threshold. Sterilization device (9) according to claim 4.

6. the second sterilization equipment (7) comprises a hydrogen peroxide spray tank (70) configured to spray vaporized hydrogen peroxide onto at least the portions (P1, P2, P3) of the web (4); A sterilization device (9) according to any one of claims 1 to 5.

7. the movement sensor (11) comprises a rotary encoder integrated in a conveyor (22) configured to advance the web (4); A sterilization device (9) according to any one of claims 1 to 6.

8. The conveyor (22) is not subject to actuation forces. Sterilization device (9) according to claim 7.

9. the control unit (12) is configured to send an alarm signal if the traveled distance (D) is greater than a predetermined distance; Preferably, the predetermined distance corresponds to the distance (D1) between the first sterilization equipment (10) and the outlet (92) of the sterilization device (9). A sterilization device (9) according to any one of claims 1 to 8.

10. the control unit (12) is configured to resume the advancement of the web of packaging material (4) after the sterilization step by the second sterilization equipment (7) is completed; A sterilization device (9) according to any one of claims 1 to 9.

11. the second sterilization device (7) is configured to sterilize the portions (P1, P2, P3) of the web (4) and the first sterilization device (10); A sterilization device (9) according to any one of the preceding claims.

12. A packaging machine (1) for producing sealed packages (2) of pourable products from a web (4) of packaging material, said packaging machine (1) comprising: A sterilization device (9) according to any one of claims 1 to 11, an isolation chamber (14) connected to the sterilization device (9) and separating an internal environment (15) from an external environment (16); a tube forming device (17) disposed at least partially within the isolation chamber (14) and configured to form a tube (3) from the web of packaging material (4); a sealing device (19) disposed at least partially within the isolation chamber (14) and configured to longitudinally seal the tube (3) formed by the tube forming device (17); a filling unit (20) adapted to fill said tube (3) with a pourable product; a package forming unit (21) configured to form and transversely seal the tube (3) to form the package (2); a plurality of conveyors (22, 23) configured to advance the web (4) of packaging material along a web advancement path (P) and to advance the tube (3) along a tube advancement path (Q); A packaging machine (1) comprising:

13. The conveyor (22) is provided upstream of the sterilization device (9), and the movement sensor (11) includes a rotary encoder incorporated in the conveyor (22). Packaging machine (1) according to claim 12.

14. the plurality of conveyors comprises at least one conveyor upstream of the sterilizer (9) including an actuator configured to control the braking speed of the advancing web (4) and / or an actuator configured to control the tension of the advancing web (4); Packaging machine (1) according to claim 12 or claim 13.

15. A method for sterilizing a web of packaging material (4), comprising the steps of: advancing said web of packaging material (4) along a web advancement path (P); sterilizing at least a first surface (5) of the advancing web (6) with a first sterilization device (10); monitoring the operation of the first sterilization equipment (10); monitoring the advancement of the web (4) along said advancement path (P); If an abnormality is detected in the operation of the first sterilization device (10): a step of preventing the advancement of said web (4); determining the distance (D) travelled by said web (4) between the detection of the anomaly and the interruption of advancement; and sterilizing at least a portion (P1, P2, P3) of the web (4) by the second sterilization device (7), the portion (P1, P2, P3) of the web being related to the traveled distance (D), method.

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