Filling machine comprising airflow system

Abstract

A paperboard container filling machine (10) comprising a sterile chamber (40) having: an upper air distribution chamber (45); a lower processing chamber (46) housing a processing device (42, 49) configured for interacting with the cardboard container passing through the processing chamber; a through-flow plate (47) separating the air distribution chamber from the process chamber, the through-flow plate having a plurality of through-openings (48) configured for directing air from the air distribution chamber to the process chamber; and a cardboard container transport subsystem configured for transporting cardboard containers through the process chamber from an inlet opening (41) to an outlet opening (43) of the process chamber along a container transport path (14). The through-flow plate comprises a substantially horizontal planar section (55) and first and second curved sections (56), each curved section presenting a convex ruled surface facing the process chamber, the ruled surface being defined by a plurality of ruled lines parallel and extending orthogonal or substantially orthogonal to the transport path.

Description

Technical Field

[0001] The present disclosure relates to a cardboard container filling machine, in particular a filling machine for producing cardboard containers for pourable food products, which cardboard containers are also referred to as cartons. In particular, the present disclosure relates to an air flow system in such a machine, for example, to an air flow system in a sterile chamber located downstream of a sterilization chamber in a cardboard container filling machine. Background Art

[0002] When pourable food products are packaged in cardboard containers in a filling machine, the containers are typically sterilized in a sterilization chamber and then transported to a sterile chamber where the containers are filled and then transported to a sterile chamber where the containers are top sealed. A first sterile chamber, sometimes referred to as a filling chamber, typically includes one or more filling devices, each filling device including a filling nozzle and a filling valve through which the pourable food product is dispensed into the container, and the filling valve controls the flow of the pourable food product through the filling nozzle, typically metering the pourable food product according to the size of the container being filled. A second sterile chamber, sometimes referred to as a sealing chamber, typically includes one or more sealing jaws configured to seal the container.

[0003] In order to prevent any type of contamination and maintain the sterile conditions of the containers established in the sterilization chamber, it is advantageous to provide a sterile and uniform air flow in the sterile chamber. However, due to the moving parts in the sterile chamber, in particular the processing equipment for performing the filling and sealing of the containers, it can be challenging to maintain a uniform air flow in the sterile chamber. Moreover, the containers themselves being transported through the filling machine may disrupt the air flow in the sterile chamber. In addition, due to the containers moving into and out of the sterile chamber, it is difficult to maintain the airtightness of the sterile chamber. The combination of turbulent air flow in the sterile chamber and a non-airtight sterile chamber may result in impure air infiltrating into the sterile chamber and contaminating the filling machine equipment and / or the containers.

[0004] An object of the present disclosure is to provide a cardboard filling machine having an improved air flow in the sterile chamber. Another object of the present disclosure is to provide a uniform cleaning air flow through the sterile chamber. Summary of the Invention

[0005] According to a first aspect, the present disclosure provides a cardboard container filling machine including a sterile chamber, the sterile chamber including:

[0006] An upper air distribution chamber;

[0007] A lower processing chamber housing processing equipment configured to interact with cardboard containers passing through the processing chamber;

[0008] A flow-through plate separates the air distribution chamber from the processing chamber. The flow-through plate includes a plurality of through openings configured to direct air from the air distribution chamber to the processing chamber, and

[0009] A cardboard container conveying subsystem configured to convey cardboard containers along a container conveying path through the processing chamber from an inlet opening to an outlet opening of the processing chamber,

[0010] The flow-through plate includes a substantially horizontal planar section and a first curved section and a second curved section. Each curved section presents a convex ruled surface facing the processing chamber. The ruled surface is defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to the conveying path.

[0011] The through openings can be slits. The slits can be straight.

[0012] The slits can be arranged along a plurality of parallel lines.

[0013] The slits can be aligned with the container conveying path.

[0014] The through openings can occupy any of the following: 5% - 50% of the total area of the flow-through plate; and 10% - 30% of the total area of the flow-through plate.

[0015] The filling machine can include an elongated air distribution duct configured to receive air from an air supply passage. The air distribution duct includes a plurality of through holes configured to distribute air in the air distribution chamber. The air distribution duct presents a semi-tubular convex surface facing the flow-through plate and has a straight duct axis that extends orthogonally or substantially orthogonally to the container conveying path.

[0016] According to a second aspect, the present disclosure provides a method for establishing an air flow in a sterile chamber of a cardboard container filling machine. The sterile chamber includes:

[0017] An upper air distribution chamber;

[0018] A lower processing chamber that houses processing equipment configured to interact with cardboard containers passing through the processing chamber; and

[0019] A cardboard container conveying subsystem configured to convey cardboard containers along a container conveying path through the processing chamber from an inlet opening to an outlet opening of the processing chamber.

[0020] The method includes the step of bringing air from the distribution chamber to the treatment chamber through a flow-through plate, the flow-through plate including a substantially horizontal planar section and a first curved section and a second curved section, each curved section presenting a convex ruled surface facing the treatment chamber, the ruled surface being defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to the transport path.

[0021] According to another aspect, the present disclosure provides a carton container filling machine including a sterile chamber, the sterile chamber including:

[0022] an upper air distribution chamber;

[0023] a lower treatment chamber housing treatment equipment configured to interact with carton containers passing through the treatment chamber;

[0024] a flow-through plate separating the air distribution chamber from the treatment chamber; and

[0025] a carton container transport subsystem configured to transport carton containers along a container transport path from an inlet opening to an outlet opening of the treatment chamber through the treatment chamber.

[0026] The flow-through plate has a predetermined thickness and includes a plurality of slits configured to direct air from the air distribution chamber to the treatment chamber, the slits having a predetermined length, a predetermined width, and a predetermined length / width ratio, wherein the predetermined thickness is at least 1.5 times the predetermined width, and wherein the predetermined length / width ratio is greater than any one of: 4, 6, 8, 10, 15, and 20.

[0027] The slits can be straight and / or arranged along a plurality of parallel lines.

[0028] The slits can occupy any one of: 5%-50% of the total area of the flow-through plate; and 10%-30% of the total area of the flow-through plate.

[0029] The slits can be aligned with the container transport path.

[0030] The flow-through plate can be planar. The slits can be arranged parallel or substantially parallel to each other.

[0031] The slits can be aligned parallel or substantially parallel to the transport path.

[0032] The flow-through plate can include a substantially horizontal planar section and a first curved section and a second curved section, each curved section presenting a convex ruled surface facing the treatment chamber, the ruled surface being defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to the transport path.

[0033] According to another aspect, the present disclosure provides a method for establishing an air flow in a sterile chamber of a cardboard container filling machine, the sterile chamber including:

[0034] An upper air distribution chamber configured to receive air from an air supply passage;

[0035] A lower processing chamber housing processing equipment configured to interact with cardboard containers passing through the processing chamber; and

[0036] A cardboard container transport subsystem configured to transport cardboard containers along a container transport path through the processing chamber from an inlet opening to an outlet opening of the processing chamber,

[0037] The method includes the step of bringing air from the distribution chamber to the processing chamber through a flow-through plate having a predetermined thickness and including a plurality of slits configured to direct air from the air distribution chamber to the processing chamber, the slits having a predetermined length, a predetermined width, and a predetermined length / width ratio, wherein the predetermined thickness is at least 1.5 times the predetermined width, and wherein the predetermined length / width ratio is greater than any one of: 4, 6, 8, 10, 15, and 20.

[0038] According to another aspect, the present disclosure provides a cardboard container filling machine including a sterile chamber, the sterile chamber including:

[0039] An upper air distribution chamber;

[0040] A lower processing chamber housing processing equipment configured to interact with cardboard containers passing through the processing chamber;

[0041] A flow-through plate separating the air distribution chamber from the processing chamber;

[0042] A cardboard container transport subsystem configured to transport cardboard containers along a container transport path through the processing chamber from an inlet opening to an outlet opening of the processing chamber; and

[0043] An elongate air distribution duct configured to receive air from an air supply passage and including a plurality of flow-through holes configured to distribute air in the air distribution chamber.

[0044] The air distribution duct presents a semi-tubular convex surface facing the flow-through plate and has a straight duct axis extending orthogonally or substantially orthogonally to the container transport path.

[0045] The flow-through holes may be circular.

[0046] According to another aspect, the present disclosure provides a method for establishing an air flow in a sterile chamber of a cardboard container filling machine, the sterile chamber including:

[0047] Upper air distribution chamber;

[0048] Lower processing chamber, housing processing equipment configured to interact with cardboard containers passing through the processing chamber;

[0049] Flow-through plate, separating the air distribution chamber from the processing chamber; and

[0050] Cardboard container conveying subsystem, configured to convey cardboard containers along a container conveying path through the processing chamber from an inlet opening to an outlet opening of the processing chamber,

[0051] The method includes the step of distributing air in the air distribution chamber by bringing air from an air supply passage through an air distribution duct to the air distribution chamber, the air distribution duct including a plurality of flow-through holes configured to distribute air in the air distribution chamber, the air distribution duct presenting a semi-tubular convex surface facing the flow-through plate and having a straight duct axis extending orthogonally or substantially orthogonally to the container conveying path.

[0052] According to another aspect, the present disclosure provides an air flow system for a sterile chamber in a dumpable food container filling machine for blank feeding. The sterile chamber may include at least one inlet opening and at least one outlet opening for container passage, and a container conveying subsystem configured to convey a container along a container conveying path through the sterile chamber from the inlet opening to the outlet opening. Typically, the container will be conveyed through a disinfection chamber before reaching the sterile chamber. The conveying subsystem may be a conveyor-based system or any other type of subsystem capable of conveying the container. The sterile chamber includes: an upper air distribution chamber configured to receive air from at least one air supply passage; a lower processing chamber housing processing equipment configured to interact with the container; and a flow-through plate separating the distribution chamber from the processing chamber. Preferably, the flow-through plate extends above the entire interface between the upper air distribution chamber and the lower processing chamber. The flow-through plate includes a plurality of slits configured to direct air from the air distribution chamber to the lower processing chamber. The slits may be aligned parallel or substantially parallel to the conveying path.

[0053] In one embodiment of the air flow system, the air distribution chamber includes at least one elongated air distribution duct receiving air from the air supply passage, wherein the at least one air distribution duct includes a plurality of flow-through holes configured to distribute air in the upper air distribution chamber.

[0054] In one embodiment of the air flow system, the air distribution duct is connected to the top wall of the air distribution chamber and presents a semi-tubular convex surface facing the flow-through plate.

[0055] In one embodiment of the air flow system, the air distribution duct has a straight duct axis that extends orthogonally or substantially orthogonally to the container transport path.

[0056] In one embodiment of the air flow system, the flow-through plate is planar and is arranged horizontally or substantially horizontally in the sterile chamber.

[0057] In one embodiment of the air flow system, the sterile chamber is a sterile filling chamber including a filling nozzle, and the flow-through plate is positioned at a height above the dispensing opening of the filling nozzle.

[0058] In one embodiment of the air flow system, the at least one flow-through plate includes a substantially horizontal planar section and a first curved section and a second curved section, each curved section presenting a convex ruled surface facing the lower processing chamber, the ruled surface being defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to the transport path.

[0059] In one embodiment of the air flow system, the flow-through plate symmetrically encloses the at least one elongated distribution duct.

[0060] In one embodiment of the air flow system, the flow-through plate is positioned in the sterile seal chamber.

[0061] In one embodiment of the air flow system, the system further includes a bottom wall having at least one exhaust outlet. Suction can be provided to the outlet.

[0062] In one embodiment of the air flow system, the slits are evenly spaced on the flow-through plate.

[0063] In one embodiment of the air flow system, the slits occupy 5% - 50% of the total area of the flow-through plate; more preferably 10% - 30% of the total area of the flow-through plate.

[0064] In one embodiment of the air flow system, the length / width ratio of the slits is greater than any of the following: 4, 6, 8, 10, 15, and 20.

[0065] In one embodiment of the air flow system, the angle of the slits relative to the transport path does not deviate from parallel by more than any of 2 degrees, 4 degrees, 6 degrees, 8 degrees, 10 degrees, 15 degrees, and 20 degrees.

[0066] Another aspect of the present disclosure relates to a method for establishing an air flow in a sterile chamber as described above, the method including the step of guiding air from an air distribution chamber to a processing chamber through the slits.

[0067] In one embodiment of the method, the method further includes the steps of subjecting an upper air distribution chamber to a first pressure and subjecting a lower processing chamber to a second pressure, the second pressure being lower than the first pressure but higher than the ambient pressure.

[0068] The various aspects and their features can be used in combination with each other.

[0069] The appended claims define the scope of protection sought. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] To facilitate understanding of the present disclosure, reference is made to the accompanying drawings. In the drawings, like reference numerals denote like features unless otherwise specified.

[0071] Figure 1 A container filling machine including a sterile filling chamber and a sterile sealing chamber is shown.

[0072] Figure 2 Shown in more detail is a container filling machine according to Figure 1 wherein the side plates are removed.

[0073] Figure 3 Shown in perspective view from below is a container filling machine according to Figure 2

[0074] Figure 4 Shown in perspective view from above is a container filling machine according to Figure 1

[0075] Figure 5 Shown in perspective view is a sterile filling chamber and a sterile sealing chamber according to Figure 1

[0076] Figure 6 Shown are an inlet opening and an outlet opening in a sterile filling chamber and a sterile sealing chamber according to Figure 1

[0077] Figure 7 Shown is an embodiment of a flow-through plate for a sterile filling chamber.

[0078] Figure 8 Shown is a close-up view of a flow-through plate according to Figure 7

[0079] Figure 9 Shown is an embodiment of a flow-through plate for a sterile sealing chamber.

[0080] Figure 10 Shown is an embodiment of an air distribution duct.

[0081] Figure 11 Shown is a processing chamber of a filling chamber and a sealing chamber of an embodiment of a filling machine. Detailed implementation manners

[0082] Embodiments of a cardboard container filling machine 10 for blank feeding according to the present disclosure will be discussed in more detail with reference to the accompanying drawings.

[0083] The filling machine 10 includes a disinfection chamber 20 configured to disinfect a top-opening cardboard container (not shown) folded from a blank (not shown).

[0084] The filling machine 10 further includes a first sterile chamber 30 disposed downstream of the disinfection chamber and forming the filling chamber of the filling machine 10. The filling chamber 30 is configured to fill the disinfected top-opening cardboard container with a pourable food. To this end, a filling nozzle 32 is disposed in the filling chamber 30. The food is supplied from a food supply system 11 (see Figure 1 ) to the filling nozzle 32.

[0085] The filling machine 10 further includes a second sterile chamber 40 disposed downstream of the filling chamber 30 and forming the sealing chamber of the filling machine 10. The sealing chamber 40 is configured to top-seal the cardboard container that has been filled in the filling chamber 30. To this end, a folding and sealing device 42 is disposed in the sealing chamber 40 (see Figure 2 ). In addition, the sealing chamber 40 may include a nitrogen flushing nozzle 49 disposed to fill the remaining space in the container with nitrogen before the container is sealed.

[0086] Thus, after passing through the disinfection chamber 20, the container first passes through the filling chamber 30, where the container is filled with a pourable food. After passing through the filling chamber 30, the container passes through the sealing chamber 40, where the container is sealed.

[0087] Both the filling chamber 30 and the sealing chamber 40 are sterile chambers that provide a sufficiently sterile environment to give the filled container a predetermined shelf life. Thus, the sterile nature of the filling chamber 30 and the sealing chamber 40 inhibits contaminants that could otherwise reduce the shelf life of the filled container. Such contaminants can be, for example, bacteria, viruses, or other microorganisms. Both the filling chamber 30 and the sealing chamber 40 include cleaning nozzles 22 that allow the chambers 30, 40 to be dosed with a cleaning fluid during a cleaning cycle.

[0088] To maintain aseptic conditions for the container and the food until the container is safely sealed, the filling machine 10 includes a first air flow system 34 configured to provide a controlled clean air flow through the filling chamber 30; and a second air flow system 44 configured to provide a controlled clean air flow through the sealing chamber 40. The clean air can be, for example, disinfected or near-disinfected air, sterile air, or HEPA air. HEPA air is produced by filtering air through a high-efficiency particulate air (HEPA) filter. As will be discussed in more detail below, the air flow systems 34, 44 are configured to provide an air flow of clean air that envelopes the container as the container is processed by the processing equipment in the filling chamber and the sealing chamber.

[0089] The container transport subsystem 12 is configured to transport each container along a transport path 14 through the filling machine 10, including through the filling chamber 30 and the sealing chamber 40 (see Figure 4 ). The container transport subsystem 12 can include a conveyor or a linear actuator configured to transport a carrier for the containers through the filling machine 10. In the disclosed embodiment, the filling machine 10 includes three parallel container transport paths 14, and the container transport subsystem 12 includes a carrier 16 configured to carry three containers in parallel (see Figure 4 - the container transport subsystem 12 is disclosed as being without containers). In this embodiment, each container transport path 14 is straight. In other words, the container transport subsystem 12 is configured to transport the containers through the filling machine along straight and parallel paths.

[0090] The filling chamber 30 is provided with an inlet opening 31 arranged to allow the containers to be transported into the filling chamber 30 by the container transport subsystem (see Figure 6 ). The filling chamber 30 is also provided with an outlet opening 33 arranged to allow the containers to be transported out of the filling chamber 30 by the container transport subsystem. Similarly, the sealing chamber 40 is provided with an inlet opening 41 arranged to allow the containers to be transported into the sealing chamber 40 by the container transport subsystem and an outlet opening 43 arranged to allow the containers to be transported out of the sealing chamber 40. The outlet opening 33 of the filling chamber 30 can form the inlet opening 41 of the sealing chamber 40, thus allowing the containers to be transported directly from the filling chamber 30 to the sealing chamber 40.

[0091] In the filling chamber 30, the containers are transported from the inlet opening 31 to the outlet opening 33 along the parallel and straight container transport paths 14. Similarly, in the sealing chamber 40, the containers are transported from the inlet opening 41 to the outlet opening 43 along the parallel and straight container transport paths 14.

[0092] The filling chamber 30 includes an upper air distribution chamber 35 and a lower processing chamber 36 (see Figure 2 ). The filling chamber 30 also includes a flow-through plate 37 for separating the air distribution chamber 35 from the processing chamber 36 (also seeFigure 3 ). The flow-through plate 37 can be integral, i.e., manufactured as a solid, uninterrupted workpiece. However, preferably, the flow-through plate 37 consists of several partial plates 37a - 37d, which together separate the air distribution chamber 35 from the processing chamber 36, for example as Figure 7 shown.

[0093] The air distribution chamber 35 is configured to receive clean air from the air supply channel 18, and the flow-through plate 37 includes a plurality of slits 38 (e.g., see Figure 8 ), which are configured to direct the clean air from the air distribution chamber 35 to the processing chamber 36. As mentioned before, the clean air can be, for example, disinfected or near-disinfected air, sterile air, or HEPA air. In other words, the clean air is provided from the air supply channel 18, and the resulting air flow flows from the air distribution chamber 35 through the flow-through plate 37 to the processing chamber 36. In the processing chamber 36, the filling nozzle 32 is configured to dispense food into the container.

[0094] In the present embodiment, the air distribution chamber 35 is configured to receive clean air from four air supply channels 18 (e.g., see Figure 3 ). However, in other embodiments, the air distribution chamber 35 can be configured to receive clean air from one, two, three, five, or more air supply channels.

[0095] The flow-through plate 37 is preferably planar, and the slits 38 are preferably aligned parallel or substantially parallel to the container transport path 14. The purpose of this configuration is to enclose the container in a uniform clean air flow that flows from the flow-through plate 37 to the carrier 16. Preferably, the uniform air flow fills the entire processing chamber 36 without forming turbulent vortices or eddies, thereby preventing contaminated air from being sucked into the filling chamber from outside the processing chamber 36, especially via an opening 60 formed in the bottom wall or floor 61 of the processing chamber 36, which is configured to receive the container to be filled (see Figure 11 ). Preferably, in the processing chamber 36, the sterile zone should extend from the flow-through plate 37 all the way down to the bottom wall 61, thereby preventing contaminated air from entering the open container that extends through the opening 60 (the top of the container is held above the bottom wall 61 by the carrier 16).

[0096] The flow-through plate 37 can be presented as a continuous surface, which is interrupted only by the slits 38 and the openings (e.g., the opening 26 for the filling nozzle and the opening 27 for the cleaning fluid pipe (see Figure 7 )) occupied by the necessary processing equipment that extends through the flow-through plate 37.

[0097] As Figure 8As shown, the slit 38 has a large aspect ratio, i.e., a large length / width ratio. Preferably, the aspect ratio of the slit 38 is greater than any of the following: 4, 6, 8, 10, 15, and 20. However, as long as the flow-through plate is structurally reliable, the aspect ratio of the slit can even be larger. According to one embodiment, the aspect ratio of the slit 38 is in the range of 5 - 30, or more preferably in the range of 10 - 20. According to one embodiment, the length L of each slit 38 can be in the range of 10 mm - 40 mm, and the width W is in the range of 5 mm - 30 mm, or more preferably in the range of 10 mm - 20 mm. The flow-through plate 37 can be made of a stainless steel metal plate with a thickness T in the range of 1 mm - 5 mm. The slit 38 can occupy 5% - 50% of the total area of the flow-through plate 37, preferably 10% - 30% of the total area of the flow-through plate. Preferably, the slits 38 are arranged evenly spaced on the flow-through plate 38.

[0098] As described above, the slit 38 can be aligned parallel to the transport path 14 of the container. It has been found that this alignment causes relatively little turbulence in the processing chamber 36. Without wishing to be bound by theory, it is believed that this alignment of the slit 38 provides a stable parallel "air knife" that is relatively unaffected by the container as the container moves through the processing chamber 36, and thus causes limited or no turbulence in the cleaning air stream. As described above, it has been found that an elongated slit aligned parallel or substantially parallel to the transport path 14 of the container causes relatively little turbulence in the processing chamber 36. A small angle of the slit 38 relative to the transport path 14 will produce a similar but less favorable effect. It has been found that the angle of the slit 38 relative to the transport path 14 preferably should not deviate from parallel by more than any one of 2 degrees, 4 degrees, 6 degrees, 8 degrees, 10 degrees, 15 degrees, and 20 degrees.

[0099] Preferably, the slit 38 is provided with rounded ends, as Figure 8 shown. This can be advantageous for cleaning because materials with 90-degree angles are more difficult to keep clean.

[0100] In Figure 2 and Figure 3 the preferred embodiment shown, in addition to the flow-through plate 37, the first air flow system 34 further includes an elongated air distribution duct 50 configured to receive the cleaning air from the air supply passage 18 and distribute the cleaning air into the air distribution chamber 35. Each air distribution duct 50 includes a plurality of flow-through holes 51 (see Figure 10 ). In the air distribution chamber 35, each air distribution duct 50 can be connected to the top wall or roof 39 of the air distribution chamber (see Figure 2), for distributing the supplied air throughout the air distribution chamber 35. The purpose of the air distribution ducts 50 is to equalize the pressure gradient within the air distribution chamber 35 in order to provide a more uniform air flow through all parts of the flow-through plate 37.

[0101] In a preferred embodiment, each air distribution duct 50 is substantially semi-tubular and includes a convex surface 52 facing the flow-through plate 37 (see Figure 3 and Figure 10 ). Advantageously, the air distribution ducts 50 extend from one side of the air distribution chamber 35 to its opposite side. Preferably, each air distribution duct 50 has a straight duct axis A (see Figure 6 ) that extends substantially orthogonally to the container transport path 14 (see Figure 3 ). Additionally, the size and / or distribution of the flow-through holes 51 can be adjusted according to the distance from the air supply passage 18 to obtain the same flow rate per unit area across the entire air distribution duct 50.

[0102] In Figure 2 and Figure 3 the preferred embodiment shown, the flow-through plate 37 is substantially planar and is positioned horizontally in the filling chamber 30 at a height directly above the lower part of the filling nozzle 32. To accommodate the filling nozzle 32 and the food supply system 11, the flow-through plate 37 can be cut or shaped as shown in Figure 7 . Preferably, the flow-through plate fits closely to the filling nozzle 32 and the food supply system 11 to avoid large openings that could cause non-uniform flow of the cleaning air from the air distribution chamber 35 to the processing chamber 36.

[0103] The sealing chamber 40, like the filling chamber 30, includes an upper air distribution chamber 45 and a lower processing chamber 46 (see Figure 2 ). The sealing chamber 40 also includes a flow-through plate 47 that separates the air distribution chamber 45 from the processing chamber 46 (also see Figure 3 ). The air distribution chamber 45 is configured to receive cleaning air from the air supply passage 19, and the flow-through plate 47 includes a plurality of slits 48 (e.g., see Figure 9 ) that are configured to direct the cleaning air from the air distribution chamber 45 to the processing chamber 46. As previously mentioned, the cleaning air can be, for example, disinfected or near-disinfected air, sterile air, or HEPA air.

[0104] In this embodiment, the air distribution chamber 45 is configured to receive cleaning air from three air supply passages 19 (e.g., see Figure 3 ). However, in other embodiments, the air distribution chamber 45 can be configured to receive cleaning air from one, two, four, five, or more air supply passages.

[0105] In a preferred embodiment, the flow-through plate 47 includes a planar section 55 and two curved sections 56 which adjoin the planar section 55 and are connected to the top wall or roof 57 of the sealing chamber 40 (see, for example, Figure 2 ). The planar section 55 is horizontally aligned so as to present a downward-facing planar surface facing the processing chamber 46. Each of the curved sections 56 presents a convex ruled surface facing the processing chamber 46, the ruled surface being defined by a plurality of rulings which are parallel and extend orthogonally or substantially orthogonally to the container transport path 14. Thus, the flow-through plate 47 presents a generally U-shaped cross-section. This configuration provides space in the processing chamber 46 for processing equipment such as the folding and sealing device 42 and the nitrogen flushing nozzle 49 (see Figure 2 ). In the lateral direction of the sealing chamber 40, the flow-through plate 47 extends across the width of the sealing chamber 40 and adjoins the side walls of the sealing chamber 40.

[0106] Similar to the slit 38, the slit 48 has a large aspect ratio. Preferably, the aspect ratio of the slit 48 is greater than any one of the following: 4, 6, 8, 10, 15, and 20. According to one embodiment, the aspect ratio of the slit 48 is in the range of 5 - 30, or more preferably in the range of 10 - 20. According to one embodiment, the length of each slit 48 can be in the range of 10 mm - 40 mm, and the width can be in the range of 5 mm - 30 mm, or more preferably in the range of 10 mm - 20 mm. The flow-through plate 47 can be made of a stainless steel sheet having a thickness in the range of 1 mm - 5 mm. The slit 48 can occupy 5% - 50% of the total area of the flow-through plate 47, preferably 10% - 30% of the total area of the flow-through plate 47. Preferably, the slits 48 are arranged at uniformly spaced intervals on the flow-through plate 48. The flow-through plate 47 can include rectangular and planar partial sections 47a - 47k which adjoin to form the flow-through plate 47, as Figure 9 shown.

[0107] The slit 48 is aligned with the container transport path 14. Thus, in the planar section 55, the slit 48 is arranged substantially parallel to the container transport path 14, while in the curved section 56, the slit 48 is arranged in parallel vertical planes. It has been found that this alignment causes limited turbulence in the processing chamber 46. The purpose of this configuration of the flow-through plate 47 is to enclose the top of the container in a uniform cleaning air flow that flows from the flow-through plate 47 to the bottom wall or floor 62 of the processing chamber 46 (see Figure 11 ). Preferably, the uniform air flow will fill the entire processing chamber 46 without forming turbulent vortices or eddies, thereby preventing contaminated air from being drawn into the sealing chamber 40 from the outside, particularly via the opening formed in the bottom wall 62 of the filling chamber 30 (see Figure 11), for example an opening formed by a guiding groove 63 configured to fold the top of the container before the container is sealed at the top. Preferably, the guiding groove 63 is the only opening present in the bottom wall 62, thus contributing to the sterile area extending all the way down from the flow-through plate 47 to the bottom wall 62.

[0108] In Figure 2 and Figure 3 In the preferred embodiment shown, in addition to the flow-through plate 47, the second air flow system 44 further includes an air distribution duct 53, which is configured to receive the clean air from the air supply passage 19 and distribute the clean air into the air distribution chamber 45. The air distribution duct 53 is preferably constructed in the same manner as the air distribution duct 51 in the filling chamber 30. Thus, the air distribution duct 53 preferably includes a plurality of flow-through holes 51 (see Figure 10 ), and the air distribution duct 53 is preferably connected to the top wall or top plate 57 of the air distribution chamber 45 (see Figure 2 ) to distribute the supplied air throughout the air distribution chamber 45.

[0109] In the preferred embodiment, the air distribution duct 53 is substantially semi-tubular like the air distribution duct 50 and includes a convex surface 52 facing the flow-through plate 47 (see Figure 3 and Figure 10 ). Advantageously, the air distribution duct 53 extends from one side of the air distribution chamber 45 to its opposite side. Moreover, preferably, the air distribution duct 53 has a straight duct axis A (see Figure 6 ) that extends substantially orthogonally to the container transport path 14 (see Figure 3 ). In addition, the size and / or distribution of the flow-through holes 51 can be adjusted according to the distance from the air supply passage 19 to obtain the same flow rate per unit area throughout the air distribution duct 53. Preferably, the flow-through plate 47 symmetrically encloses the distribution duct 53.

[0110] During the operation of the filling machine 10, all the clean air flowing from the air distribution chamber 35 into the processing chamber 36 in the filling chamber 30 preferably should pass through the slit 38 in the flow-through plate 37. Then the clean air can be discharged from the processing chamber 36 through the opening 60 in the bottom wall 61 (or more precisely, through the section of the opening 60 not occupied by the container, see Figure 11 ).

[0111] Similarly, during the operation of the filling machine 10, all the clean air flowing from the air distribution chamber 45 into the processing chamber 46 in the sealing chamber 40 preferably should pass through the slit 48 in the flow-through plate 47. Then the clean air can be discharged from the processing chamber 46 through the guiding groove 63 (see Figure 11 ).

[0112] The areas of the air outlets (such as the openings 60 and the guide grooves 63) can preferably be evenly distributed along the conveying path 14 of the container filling, so as to enclose the container in a uniform air flow. In some applications, this can enhance the flow of sterile air from the through-flow plates 37, 47 towards the bottom walls 61, 62. Additionally or alternatively, suction can be provided to the air outlets. However, if suction is provided, the suction should not be so strong that the pressure in the corresponding part of the treatment chamber drops below the ambient pressure, because this may cause unclean air to enter the treatment chambers 36, 46 through any gaps.

[0113] According to the present disclosure, a method for establishing an air flow of clean air in a sterile chamber of a filling machine (such as in a filling chamber or a sealing chamber) includes the step of guiding clean air from the air distribution chambers 35, 45 through the through-flow plates 37, 47 to the treatment chambers 36, 46.

Claims

1. A cardboard container filling machine (10) including a sterile chamber (30, 40), said sterile chamber (30, 40) comprising: an upper air distribution chamber (35, 45); a lower processing chamber (36, 46) accommodating processing equipment (32, 42, 49), said processing equipment being configured to interact with cardboard containers passing through said processing chamber (36, 46); a flow-through plate (37, 47) separating said air distribution chamber (35, 45) from said processing chamber (36, 46), said flow-through plate (37, 47) including a plurality of through openings (38, 48), said through openings being configured to direct air from said air distribution chamber (35, 45) to said processing chamber (36, 46); and a cardboard container conveying subsystem (12) configured to convey said cardboard containers along a container conveying path (14) through said processing chamber (36, 46) from an inlet opening (31, 41) to an outlet opening (33, 43) of said processing chamber (36, 46), characterized in that said flow-through plate (47) includes a substantially horizontal planar section (55) and first and second curved sections (56), each said curved section (56) presenting a convex ruled surface facing said processing chamber (46), said ruled surface being defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to said conveying path (14).

2. The filling machine (10) according to claim 1, wherein, said through openings are slits (38, 48).

3. The filling machine (10) according to claim 2, wherein, said slits (38, 48) are straight.

4. The filling machine (10) according to any one of claims 2 and 3, wherein, said slits (38, 48) are arranged along a plurality of parallel lines.

5. The filling machine (10) according to any one of claims 2 to 4, wherein, said slits (38, 48) are aligned with said container conveying path (14).

6. The filling machine (10) according to any one of the preceding claims, wherein, said through openings (38, 48) occupy any of the following: 5% - 50% of the total area of said flow-through plate (37, 47); and 10% - 30% of the total area of said flow-through plate (37, 47).

7. The filling machine (10) according to any one of the preceding claims, including elongated air distribution ducts (50, 53), said air distribution ducts being configured to receive air from an air supply passage (18, 19), said air distribution ducts (50, 53) including a plurality of flow-through holes (51), said plurality of flow-through holes being configured to distribute air in said air distribution chamber (35, 45), and said air distribution ducts presenting a semi-tubular convex surface (52) facing said flow-through plate (37, 47) and having a straight duct axis (A) extending orthogonally or substantially orthogonally to said container conveying path (14).

8. A method for establishing an air flow in a sterile chamber (30, 40) of a cardboard container filling machine (10), said sterile chamber (30, 40) comprising: an upper air distribution chamber (35, 45); a lower processing chamber (36, 46) accommodating processing equipment (13), said processing equipment being configured to interact with cardboard containers passing through said processing chamber (36, 46); and a cardboard container conveying subsystem (12) configured to convey said cardboard containers along a container conveying path (14) through said processing chamber (36, 46) from an inlet opening (31, 41) to an outlet opening (33, 43) of said processing chamber (36, 46), characterized in that the method comprises the step of bringing air from said distribution chamber (45) to said processing chamber (46) through a flow-through plate (47), said flow-through plate comprising a substantially horizontal planar section (55) and a first curved section and a second curved section (56), each curved section (56) presenting a convex ruled surface facing said processing chamber (46), said ruled surface being defined by a plurality of rulings that are parallel and extend orthogonally or substantially orthogonally to said conveying path (14).

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