WO2025223687A1

WO2025223687A1 - Filling machine for filling pourable food products into package sleeves closed at the bottom or packages and method for generating a unidirectional sterlie air stream from top to bottom of such a filling machine

Info

Publication number: WO2025223687A1
Application number: PCT/EP2024/084071
Authority: WO
Inventors: Martin Barej; Christopher Thiemo Langen; Thomas Patzer; Dorothee ROGGENKAMP; Ngoc-Thinh Nguyen; Jens Kuypers; Christian Weiler; Hanno Geissler
Original assignee: SIG Services AG
Current assignee: SIG Services AG
Priority date: 2024-04-25
Filing date: 2024-11-29
Publication date: 2025-10-30
Anticipated expiration: 2026-10-25
Also published as: EP4640567A1

Abstract

Illustrated and described is a filling machine (20) for filling pourable food products into package sleeves (10) closed at the bottom or packages (P), comprising a transport device (26) for conveying the package sleeves (10) or packages (P) along a transport direction, a sterilization station (30), a bottom sealing station (34), and a filling station (35) for filling pourable food products into package sleeves (10) closed at the bottom or packages (P), wherein all aforesaid stations are arranged in a machine housing. In order to generate a unidirectional sterile air stream from top to bottom of such a filling machine in a suitable and effective way, the filling machine (20) further comprises at least one pre-distribution unit (42, 42') for a homogenization of sterile air being introduced from above into the filling machine (20) at least in areas where a uniform downward flow is required, and in that each pre-distribution unit (42, 42') comprises at least one perforated plate (45, 45') arranged above at least one layer of porous material. Furthermore, two methods for generating a unidirectional sterile air stream from top to bottom of a filling machine (20) comprise the following steps: - supply of sterile air into a pre-distribution unit (42), - division of the centrally supplied sterile air into a downward flow and a radially outward flow at the top of a box-shaped perforated plate (45) or a strip-shaped perforated plate (45') arranged in the pre-distribution unit (42 or 42'), to reduce its flow velocity, - redirecting the sterile air vertically downwards when leaving the box-shaped perforated plate (45) or the strip-shaped perforated plate (45') through a layer of porous material, to homogenize the velocity of the air flow.

Description

Filling machine for filling pourable food products into package sleeves closed at the bottom or packages and method for generating a unidirectional sterile air stream from top to bottom of such a filling machine

The invention relates to a filling machine for filling pourable food products into package sleeves closed at the bottom or packages, comprising: a transport device for conveying the package sleeves or packages along a transport direction, a sterilization station, a bottom sealing station, and a filling station for filling pourable food products into package sleeves closed at the bottom or packages, wherein all aforesaid stations are arranged in a machine housing.

Moreover, the invention relates to methods for generating a unidirectional sterile air stream from top to bottom of such a filling machine according to claims 16 and 17.

Such a filling machine is known from WO 2023/016693 Al. These known filling machines may comprise a sterile air chamber around at least the aseptic zone to avoid dust or germs entering the machine, wherein the sterile air chamber is continuously supplied with sterile air from top to bottom as described in WO 2023/016692 Al.

To ensure a proper operation of the filling machine, it is necessary to reduce turbulent air flows in particular parts inside the machine as much as possible. Therefore, the moving packing elements should be transported through a uniform and vertically unidirectional flow at least in the drying region at the end of the sterilization station and/or in the aseptic zone. However, in some areas of the machine, e.g., in the sterilization zone, turbulence is not a bad thing at all to ensure that the H2O2 gets into contact with all surfaces.

It is therefore an object of the invention to modify the known filling machine in order to generate a unidirectional sterile air stream from top to bottom of such a filling machine in a suitable and effective way.

For a filling machine according to the preamble of claim 1, the aforesaid object is solved in that the filling machine further comprises at least one pre-distribution unit for a homogenization of sterile air being introduced from above into the filling machine at least in areas where a uniform downward flow is required, and in that each pre-distribution unit comprises at least one perforated plate. Preferably, each pre-distribution unit comprises two or more perforated plates.

The aforesaid object is also reliably solved by a first method for generating a unidirectional sterile air stream from top to bottom of a filling machine according to claims 6 to 16, comprising the following steps: supply of sterile air into a pre-distribution unit, division of the centrally supplied sterile air into a downward flow and a radially outward flow at the top of a box-shaped perforated plate arranged in the predistribution unit, to reduce its flow velocity, redirecting the sterile air vertically downwards when leaving the box-shaped perforated plate through a layer of porous material, to homogenize the velocity of the air flow.

Alternatively or cumulatively, the aforesaid object is also solved by a second method for generating a unidirectional sterile air stream from top to bottom of a filling machine according to claims 7 to 16, comprising the following steps: supply of sterile air into a pre-distribution unit, division of the centrally supplied sterile air into a downward flow and a radially outward flow at the top of a strip-shaped perforated plate arranged in the predistribution unit, to reduce its flow velocity, redirecting the sterile air vertically downwards when leaving the strip-shaped perforated plate through a layer of porous material, to homogenize the velocity of the air flow.

Advantageously, according to a preferred embodiment, each pre-distribution unit comprises at least one flow resistor. In addition to the perforated plate, the flow resistor is an additional flow-resisting element through which the air flow is directed with increased air resistance. The flow resistor can be a perforated plate or a layer of porous material. The layer of porous material can be made of a porous polymer, particularly a microporous sintered polyethylene. The main effect of the layer of porous material is to homogenize the vector lengths, i.e., the speed of the air flow.

Advantageously, according to a preferred embodiment, the at least one perforated plate is arranged above a flow resistor, in particular above at least one additional perforated plate or above at least one layer of porous material. An additional flow resistor such as at least one additional perforated plate or at least one layer of porous material arranged under the perforated plate causes air to accumulate and the air flowing in from the sides to mix with the air flowing in from above. This creates a uniform velocity distribution when the air flows into the panel of porous material.

Advantageously, according to a preferred embodiment, the filling machine comprises at least one vertical inlet pipe above each pre-distribution unit, preferably centrally arranged above each pre-distribution unit. This allows a uniformly distributed air intake inside the filling machine. In case hot sterile air is required, the inlet pipe might be heated from outside.

According to a first embodiment, the perforated plate is box-shaped, and its perforation is evenly distributed. However, the perforation of the box-shaped perforated plate might be designed differently in the area under the inlet pipe, for example, with smaller or fewer openings in order to increase the second partial air flow. The main flow of sterile air is divided inside the pre-distribution unit: one part flows directly downwards into the box-shaped perforated plate, another part is distributed around the box-shaped perforated plate. This ensures that the second partial flow is distributed over a large area outside the box, and, accordingly, the flow velocity decreases and the sterile air flows into the box from all sides resulting in a reduction of the flow momentum, i.e., all fast jets are eliminated.

Alternatively, or cumulatively, the perforated plate is designed as an angled strip, the perforation of which is evenly distributed. Such a strip-shaped perforated plate is contained in an elongated box which is arranged perpendicular to the transport direction of the package sleeves or packages of the filling machine. This construction ensures that the unidirectional sterile air flow is generated from top to bottom of a filling machine underneath the box over a length in the transport direction, which is defined by the width of the elongated box. This allows to create a unidirectional sterile air flow just for a single station, e.g., the hot air station.

The perforated plates may have a plurality of holes as openings. This allows an easy production and processing, either for box-shaped or strip-shaped perforated plates. However, it is also possible to choose perforations with made from slotted holes or slots. Moreover, gill-like slots can also be used if the flow direction needs to be changed or adjusted.

The use of parallel perforated plates to generate laminar flow in filling machines is known as such (WO 2006/053 746 Al).

According to a further preferred embodiment of the invention, each box-shaped perforated plate comprises a horizontal flange circumferential on all sides. In case of strip-shaped perforated plates, the horizontal flanges are arranged at the narrow ends of the angled strips. Preferably, also the horizontal flanges have a perforated design. More preferred, the perforation of the horizontal flange is identical to the perforation of the box-shaped or strip-shaped perforated plate. This again allows a simplified prefabrication of such boxes or of the angled strips.

According to a further teaching of the present invention, the at least one layer of porous material is designed as a flat, preferably self-supporting, panel being arranged under the perforated plate in each pre-distribution unit. In a preferred embodiment, the panel of porous material is made of a porous polymer, particularly a microporous sintered polyethylene. The layer of a porous material under each perforated plate causes air to accumulate and the air flowing in from the sides to mix with the air flowing in from above. This creates a uniform velocity distribution when the air flows into the panel of porous material. The main effect of the layer of porous material is to homogenize the vector lengths, i.e., the speed of the air flow.

According to another preferred development of the present invention, a horizontal honeycomb element made of a plurality of vertically oriented and closely spaced honeycomb cells with openings on both sides is arranged under the at least one layer of porous material in each pre-distribution unit. The vertically parallel arranged honeycomb cells direct the flow of sterile air downwards. The honeycomb element may be designed as a replaceable insert for insertion in the corresponding predistribution unit. Such a design allows a simple assembly and an easy cleaning of the pre-distribution unit.

According to another teaching of the present invention, the filling machine comprises a plurality of parallel tracks for running through the package elements to be filled. In this case, preferably each pre-distribution unit spans several parallel tracks perpendicular to the transport direction of the package sleeves or packages of the filling machine. The invention will be explained in more detail below with the aid of a drawing which merely represents a preferred exemplary embodiment, in which:

Figs. 1A-F show different states of a package element during the production of a package starting from a blank of package material, a package sleeve, which is formed from such a blank in a flat-folded state, in a partially unfolded state, in the completely unfolded state with applied spout element, and a package manufactured from such a package sleeve in the filled and closed state, ready for sale,

Fig. 2 shows a preferred embodiment of a filling machine according to the invention in a schematic side view,

Fig. 3 shows a sequence of individual steps or stations of the manufacturing method,

Fig. 4 shows a first preferred embodiment of a pre-distribution unit of the present invention, in a vertical section,

Fig. 5 shows a simplified illustration of the air flows in a representation corresponding to Fig. 4,

Fig. 6 shows a box-shaped perforated plate in a perspective view,

Fig. 7 shows a part of the filling machine according to the invention in a vertical section through the area with two adjacent pre-distribution units, in a perspective view, partially enlarged,

Fig. 8 shows the left pre-distribution unit of Fig. 7 in a vertical section along the line Vlll-Vlll in Fig. 7, Fig. 9 shows a second preferred embodiment of a pre-distribution unit of the present invention, in a perspective view, without front wall of an elongated box housing the pre-distribution unit, and

Fig. 10 shows the right part of the pre-distribution unit of Fig. 9 without lid plates of the elongated box in a perspective view from above.

Fig. 1A represents a blank 1 known from the prior art, from which a package sleeve may be formed. The blank 1 may comprise a plurality of layers of different materials, for example paper, paperboard, plastic, or metal, in particular aluminium. The blank 1 has a plurality of fold lines 2, which are intended to facilitate the folding of the blank 1 and which divide the blank 1 into a plurality of surfaces.

The blank 1 may be divided into a first side surface 3, a second side surface 4, a front surface 5, a rear surface 6, a sealing surface 7, bottom surfaces 8 and gable surfaces 9. A package sleeve 10 may be formed from the blank 1 by folding the blank 1 in such a way that the sealing surface 7 can be connected, particularly welded, to the front surface 5. A round weakening line W is represented by dashes in the region of a spout element (not shown) to be sealed at a later stage.

Fig. IB shows a package sleeve 10 known from the prior art in the flat-folded state. The regions of the package sleeve 10 which have already been described in connection with Fig. 1A are provided with corresponding references in Fig. IB. The package sleeve 10 is formed from the blank 1 shown in Fig. 1A. For this purpose, the blank 1 has been folded in such a way that the sealing surface 7 and the front surface 5 are arranged overlapping, so that the two surfaces can be welded together over their surfaces. A longitudinal seam 11 is obtained as a result.

In Fig. IB, one side surface 4 (concealed in Fig. IB) lies underneath the front surface 5, while the other side surface 3 lies on the rear surface 6 (concealed in Fig. IB). In the flat-folded state, a plurality of package sleeves 10 may be stacked in a particularly space-saving manner. The flat-folded package sleeves 10 are therefore often stacked at the place of manufacturing and transported in stacked form to the place of filling. Only then are the package sleeves 10 unstacked and unfolded so that, after sealing the bottom, they can be filled with contents, for example with pourable foodstuffs.

Fig. 1C shows the package sleeve 10 of Fig. IB in a partially unfolded state. It can easily be seen that the package sleeve 10 has surrounding open cut edges OCEs both on its top and its bottom side.

Fig. ID shows the package sleeve 10 of Fig. 1C in a completely unfolded state. In this state, a spout element S may be applied to the weakening line W (no longer visible here) and, for example, welded to the package material by means of ultrasonics. Although a package sleeve 10 with weakening line W is shown here, the present invention also includes the use of package sleeves with a hole for inserting a spout element and sealing its flange on the inside of the blank. In the exemplary embodiment shown, the spout element S is provided with a screw cap which, on the one hand, allows initial opening of the (subsequently) filled package and can furthermore be used to reclose such a package.

Moreover, the regions of the package sleeve 10 which have already been described in connection with Fig. 1A or Fig. IB are provided with corresponding references. The unfolded state refers to a configuration in which an angle of about 90° is formed between the two respectively adjacent surfaces 3, 4, 5, 6, so that the package sleeve 10 - depending on the shape of these surfaces - has a square or rectangular cross section. Accordingly, the opposite side surfaces 3, 4 are arranged parallel to one another. The same applies for the front surface 5 and the rear surface 6.

Figures IE and IF show a package P manufactured from the package sleeve 10 of Fig. ID in the (subsequently) filled and closed state. After closure, a fin seam 12 is created in the region of the bottom surface 14 and in the region of the gable surfaces at the head 15. In addition, protruding regions of excess material, which are also referred to as “ears” 13, are formed in the edge regions of the bottom surfaces 8 and the gable surfaces 9. In Fig. IE, the fin seams 12 and the ears 13 protrude. In Fig. IF, both the fin seams 12 and the ears 13 have been applied, for example by means of an adhesive method. The - upper - ears 13 created by the gable surfaces 9 are applied onto the side surfaces 3, 4, while the - lower - ears 13 created by the bottom surfaces 8 are applied onto the lower side of the package sleeve 10. In Fig. IF, the package P is therefore shown in a state ready for sale.

Fig. 2 shows - schematically - a filling machine 20 in a side view. Individual package sleeves 10 are taken of a stack 19 of package sleeves 10 and are slightly unfolded. Thereafter, the package sleeves 10 are transferred to an unfolding station 21 of the actual filling machine 20. However, the package sleeves 10 could also be unfolded beforehand so that no unfolding station 21 is required. In the illustrated embodiment, the package sleeves 10 are then lifted into an applicator station 22, provided with a spout element S by means of an ultrasonic sealing unit 23 known per se and lowered again. However, if the sleeves have just a weakening zone or an overcoated hole (OCH) in the gable, the spout element will be applied after filling and closing of the package at the end of the machine (“post-application"), so that no applicator station 22 is required. In the next, optional, position, an optical sensor system 24 checks if the package sleeve 10 provided with the spout element S for possible defects. The package sleeve 10 is then taken over in a transfer station 25 by a transport device 26. If required, an ejection station 28 can also be provided for ejecting defective package sleeves 27 that have not been correctly transferred or sleeves with a missing or incorrectly sealed spout element S.

Subsequently, a pre-folding station 29 is provided, in which both the bottom 14 and the head 15 of the carton sleeves 10 are pre-folded. The package sleeves 10 are then sterilized in a sterilization station 30. In the embodiment example shown, the sterilization station 30 has three sub stations, namely a hot air station 31 for preheating the package sleeves 10 that are still open at the bottom, a sterilizing agent station 32 for sterilizing the package sleeves by injecting a sterilizing agent and a drying station 33 for drying the sterilized package sleeves. However, the hot air station 31 is not necessary in any case.

Thereafter, the bottom sealing takes place in a bottom sealing station 34, whereby the ears formed thereby are sealed from below onto the closed bottom 14 of the package bodies 16 formed by the bottom sealing station 34. After filling the package body 16 in a subsequent filling station 35, which can take place in two subsequent steps in two filling units 36 in the present embodiment, the now filled package body 16 passes through a head closure station 37 for forming and sealing the head 14 of the package body 16, which can also be regarded as the gable of the package body 16. First in a gable seam station 38 the head seam is sealed. Second the thereby formed ears 13 are then sealed to the side surfaces 3, 4 in an ear sealing station 39, resulting in the finished package P, which is discharged at the end of the transport device 26 via a discharging station 40, particularly in a horizontal direction.

As shown in Fig. 3, the essential working steps are shown diagram-like, as well as the stations mentioned before, from the unfolding of the package sleeves 10 to the closing of the head 15 or top of the package bodies 16 take place in an aseptic zone 41.

In Fig. 4, a preferred first embodiment of a pre-distribution unit 42 of the present invention is shown in a vertical section. The pre-distribution unit 42 comprises a housing 43 with an inlet pipe 44 on top through which sterile air is introduced into the pre-distribution unit 42. In the upper part of the pre-distribution unit 42 a boxshaped perforated plate 45 is arranged having a plurality of openings, in the preferred and illustrated embodiment realized as holes or bores. Underneath of the box-shaped perforated plate 45 a layer of porous material is shown, which in this embodiment is designed as a flat, preferably self-supporting, panel 47. The panel 47 under the boxshaped perforated plate 45 causes air to accumulate and the air flowing in from the side to mix with the air flowing in from above. This creates a uniform velocity distribution when the air flows into the panel 47 of porous material. The arrows in Fig. 4 are intended to illustrate the flow of the incoming air. The strongest flow (large arrow) is shown inside of the inlet pipe 44. The main effect of the layer of porous material is to homogenize the vector lengths, i.e., the speed of the air flow as is illustrated by the shorter velocity arrows at the bottom.

Fig. 5 shows a simplified illustration of all air flows in the pre-distribution unit 42 shown in Fig. 4. Here one can see the principle of generating a unidirectional flow according to the invention, which has been optimized in terms of unidirectionality and range of the air flow. The arrangement, size and direction of the arrows show the speed and direction of the sterile air inside the pre-distribution unit 42. The main flow inside the inlet pipe 44 (large vertical arrow) is directed downwards. The top surface of the box-shaped perforated plate 45 allows one part of the vertical flow to enter the box-shaped perforated plate 45 from above and deflects the vertical flow into partial flows radially in all horizontal directions (black horizontal arrows). These partial flows enter the box through the openings on top and its four sidewalls (small black arrows).

Due to a special pre-distribution of the air and the porous material of the panel 47 a deep unidirectional flow of the sterile air can be achieved. In Fig. 6, the box-shaped perforated plate 45 is shown in a perspective view inside the pre-distribution unit 42, which is only indicated by dashed lines.

A deeper insight into the filling machine 20 according to the invention is provided by Fig. 7, showing a part of the filling machine 20 in a vertical section through the area with four adjacent pre-distribution units 42, each having inlet pipes 44 on top. Two of each pre-distribution units 42 are arranged one behind the other in the transport direction of the packages to be filled and sealed and the other ones next to each other perpendicular to said transport direction. In the preferred and illustrated embodiment, the four adjacent pre-distribution units 42 extend over six parallel tracks, of which three tracks A, B, and C on the left and three tracks D, E, and F on the right are indicated as cut open package bodies illustrated in dashed lines for a better understanding. Due to the perspective view, only the first two pre-distribution units

42 are visible in more detail.

As described already above regarding Figs. 4 and 5, a layer of porous material is shown underneath of the box-shaped perforated plate 45 of each pre-distribution unit 42, which preferably is designed as a flat panel 47. This layer of porous material is used, as already explained in more detail in the general description, as flow resistance to achieve a uniform distribution of the air flow velocity of the air flowing out of the panel 47 into the machine 20 below.

Under the panel 47, in the shown preferred embodiment, a honeycomb element 48 is arranged comprising a plurality of vertically oriented and closely spaced honeycomb cells, each having openings at the top and bottom. The honeycomb element 48 will be described in more detail below under Fig. 8.

The enlargement on the right of Fig. 7 shows the upper side of the box-shaped perforated plate 45, where a different design of the perforation directly below the inlet pipe 44 can be seen. Here, the perforation of the box-shaped perforated plate 45 is designed differently with significantly smaller openings in order to increase the second partial air flow directed radially to the sides of the box-shaped perforated plate 45, as was already described above regarding Fig. 5.

Fig. 8 shows the left pre-distribution unit 42 of Fig. 7 in a vertical section along the line VIII- VI II in Fig. 7. The vertical arrangement of the individual components is clearly visible in this enlarged view. From top to bottom, these comprise the inlet pipe 44, the roof of the housing 43, the box-shaped perforated plate 45, the panel 47, made of porous material, and a honeycomb element 48, comprising a plurality of vertically oriented and closely spaced honeycomb cells 49. The vertically parallel arranged honeycomb cells 49 direct the flow of sterile air downwards into the filling machine 20. The components listed before are attached to unspecified support elements of the pre-distribution unit 42. Fig. 9 shows a second preferred embodiment of a pre-distribution unit 42’ containing two adjacent strip-shaped perforated plates 45’, each having two horizontal flanges 46’ at their narrow ends, the view of which corresponds approximately to that of Fig. 7 above. Underneath of each strip-shaped perforated plate 45’ of pre-distribution unit 42’, one can see a flat panel 47’. Both the strip-shaped perforated plates 45’ and the flat panels 47’ are arranged one after the other in an elongated box 50 which is arranged perpendicular to the transport direction of the filling machine 20. The top of the box 50 is closed with a two-part top element comprising two lid plates 51, partially cut. A partition wall (not shown) can be provided between the adjacent predistribution units 42’ to separate them from each other.

Preferably, the sterile air supplied to the strip-shaped perforated plate 45’ is heated to be used as a drying medium in the drying station 33. In the illustrated and preferred embodiment, two heated inlet pipes 52 are arranged on top of each lid plate 51 centrally above each strip-shaped perforated plate 45’. To ensure the preferred airflow inside, the elongated box 50 is closed on all four sides by vertical wall elements. However, the front wall element is not shown in Fig. 9 to get an overview of the internal design of the pre-distribution unit 42’.

It should be noted that there are no slots between the wall elements and both the strip-shaped perforated plates 45' and the flat panels 47' to ensure that the air flow passes through all openings in each strip-shaped perforated plate 45' to achieve the desired deep, unidirectional flow of sterile air after having passed the panels 47'.

Fig. 10 shows the left pre-distribution unit 42’ of Fig. 9 in a perspective view from above. Here both front and end wall elements of the elongated box 50 are depicted and the lid plates 51 were removed. The longitudinal sides of the strip-shaped perforated plates 45’ touch the inside of the wall elements. Moreover, the strip-shaped perforated plate 45’ has a different pattern of holes in its center region for better flow distribution of the hot sterile air. The embodiments described in more detail above can be used alone or in combination thereof to achieve the individual needs for a specific filling machine to generate a unidirectional sterile air stream from top to bottom in desired areas of such a filling machine.

List of reference

OCE: open cut edge

P: package

S: spout element

W: weakening line

1: blank

2: fold line

3, 4: side surfaces

5: front surface

6: rear surface

7: sealing surface

8: bottom surface

9: gable surface

10: package sleeve

11: longitudinal seam

12: fin seam

13: ears

14: bottom

15: head

19: stack

20: filling machine

21: unfolding station

22: applicator station

23: ultrasonic sealing unit

24: optical sensor system

25: transfer station

26: transport device

27: defective package sleeve

28: ejection station 29: pre-folding station

30: sterilization station

31: hot air station

32: sterilizing agent station

33: drying station

34: bottom sealing station

35: filling station

36: filling unit

37: head closure station

38: gable seam station

39: ear sealing station

40: discharging station

41: aseptic zone

42, 42’: pre-distribution unit

43: housing

44: inlet pipe

45: perforated plate (box-shaped)

45’: perforated plate (strip-shaped)

46, 46’: horizontal flange

47, 47’: panel of sintered material

48: honeycomb element

49: honeycomb cell

50: elongated box

51: lid plate

52: heated inlet pipe

Claims

1. A filling machine (20) for filling pourable food products into package sleeves (10) closed at the bottom or packages (P), comprising: a transport device (26) for conveying the package sleeves (10) or packages

(P) along a transport direction, a sterilization station (30), a bottom sealing station (34), and a filling station (35) for filling pourable food products into package sleeves (10) closed at the bottom or packages (P), wherein all aforesaid stations are arranged in a machine housing, characterized in that the filling machine (20) further comprises at least one pre-distribution unit (42, 42’) for a homogenization of sterile air being introduced from above into the filling machine (20) at least in areas where a uniform downward flow is required, and in that each pre-distribution unit (42, 42’) comprises at least one perforated plate (45, 45’).

2. Filling machine (20) according to claim 1, characterized in that each pre-distribution unit (42, 42’) comprises at least one flow resistor.

3. Filling machine (20) according to claim 2, characterized in that the flow resistor is a perforated plate or a layer of porous material.

4. Filling machine (20) according to claims 1 to 3, characterized in that the at least one perforated plate (45, 45’) is arranged above a flow resistor, in particular above at least one additional perforated plate or above at least one layer of porous material.

5. Filling machine (20) according to claims 1 to 4, characterized in that the filling machine (20) comprises at least one vertical inlet pipe (44, 52) above each pre-distribution unit (42, 42’).

6. Filling machine (20) according to claims 1 to 5, characterized in that the perforated plate (45) is box-shaped, and in that its perforation is evenly distributed.

7. Filling machine (20) according to claims 1 to 5, characterized in that the perforated plate (45’) is an angled strip, the perforation of which is evenly distributed, and in that the perforated plate (45’) is arranged in an elongated box (50) which is arranged perpendicular to the transport direction of the package sleeves (10) or packages (P) of the filling machine (20).

8. Filling machine (20) according to claim 5 or 7, characterized in that the perforation of the perforated plate (45, 45’) is different in the area under the inlet pipe (44, 52).

9. Filling machine (20) according to claim 6, characterized in that each box-shaped perforated plate (45) comprises a horizontal flange (46) circumferential on all sides.

10. Filling machine (20) according to claim 7, characterized in that each strip-shaped perforated plate (45’) comprises horizontal flanges (46’) at its narrow ends.

11. Filling machine (20) according to claim 9 or 10, characterized in that the horizontal flange (46, 46’) has a perforated design.

12. Filling machine (20) according to claims 1 to 11, characterized in that the at least one layer of porous material is designed as a flat, preferably self- supporting, panel (47, 47’).

13. Filling machine (20) according to claim 12, characterized in that the panel (47, 47’) of porous material is made of a porous polymer, particularly a microporous sintered polyethylene.

14. Filling machine (20) according to any one of claims 1 to 13, characterized in that a horizontal honeycomb element (48) made of a plurality of vertically oriented and closely spaced honeycomb cells (49) with openings on both sides is arranged under the at least one layer of porous material.

15. Filling machine (20) according to any one of claims 1 to 14, characterized in that the filling machine (20) comprises a plurality of parallel tracks (A, B, C; D, E, F).

16. Filling machine (20) according to claim 15, characterized in that each pre-distribution unit (42, 42’) spans several parallel tracks (A, B, C; D, E, F) perpendicular to the transport direction of the package sleeves (10) or packages (P) of the filling machine (20).

17. Method for generating a unidirectional sterile air stream from top to bottom of a filling machine (20) according to claims 6 to 16, comprising the following steps: supply of sterile air into a pre-distribution unit (42), division of the centrally supplied sterile air into a downward flow and a radially outward flow at the top of a box-shaped perforated plate (45) arranged in the pre-distribution unit (42), to reduce its flow velocity, redirecting the sterile air vertically downwards when leaving the box-shaped perforated plate (45) through a layer of porous material, to homogenize the velocity of the air flow.

18. Method for generating a unidirectional sterile air stream from top to bottom of a filling machine (20) according to claims 7 to 16, comprising the following steps: supply of sterile air into a pre-distribution unit (42’), division of the centrally supplied sterile air into a downward flow and a radially outward flow at the top of a strip-shaped perforated plate (45’) arranged in the pre-distribution unit (42’), to reduce its flow velocity, redirecting the sterile air vertically downwards when leaving the strip-shaped perforated plate (45’) through a layer of porous material, to homogenize the velocity of the air flow.

19. Method according to claim 18, c h a r a c t e r i z e d i n t h a t the sterile air supplied to the strip-shaped perforated plate (45’) is heated to be used as drying medium in the drying station (33).