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(11) | EP 0 062 929 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Aseptic packaging method and apparatus |
| (57) An aseptic packaging machine 1 includes a chain conveyor conveying cartons along
a path P in an aseptic chamber 6 including an advance leg and a return leg each extending
along the machine 1. Ultra-violet germicidal lamps 8 extend over at least a major
potion of the advance leg. Aseptic liquid is fed into the cartons C by a filling device
9 comprised of, in turn, an expansion chamber, a non-return inlet valve, a reciprocatory
bellows and a non-return outlet valve. After filling, the cartons are top-heated and
sealed by a top-heating device 10 and a top-sealing device 11. The only non-aseptic
matter deliberately introduced into the chamber 6 is the cartons C. The chamber 6
is cleaned internally by cleaning fluid from spray nozzles. The canon entry to and
exit from the chamber 6 have aseptic air curtains. |
[0001] This invention relates to aseptic packaging methods and apparatus for performing the methods, particularly aseptic packaging of products, for example long-life milk, in cartons.
[0002] Federal German Specification 2214080 discloses an aseptic packaging system in which an aseptic chamber contains an endless chain conveyor which carries tub-form containers from a container supply station to a station at which the containers interiors are sprayed with sterilizing liquid. The chains carry the containers in an inverted condition along an underneath run along most of which the container interiors are exposed to drying air from perforated pipes. This drying is intended to evaporate away all of the residual sterilizing liquid. The containers are then carried along the upper run of the conveyor past a product filling station, a lidding station and a sealing station to a carton removal station. The perforated pipes can also be used for feeding sterilizing fluid therethrough, for example before the apparatus starts its operations, or in between such operations, for the purposes of cleaning or sterilization, followed by drying with sterile drying air. This latter cleaning or sterilization is of the interior of the chamber and of the items, such as the chains, therein, and is not of the interiors of the containers.
[0003] United States Patent 3566575 discloses an aseptic packaging machine in which hydrogen peroxide is sprayed into a carton at an aseptic treatment station and evaporated away at a drying station. This system has the disadvantage that, unless the carton is to remain at the drying station for an appreciable length of time, which would obviously slow down the whole machine, the drying is inefficient and results in considerable residue of hydrogen peroxide at the filling station. Also in this machine, from the aseptic treatment stage, the container top is protected by an aseptic atmosphere until it has.been filled, sealed and discharged from the machine. At an aseptic fogging and drying unit, the sterile air is supplied from a tube.to a chamber bounded at its underneath by a directional screen which distributes the air over the length and width of the unit. The air flows downwards through the screen and exits downwards through the gaps between the cartons and a split bottom cover of an air control housing. However, such an arrangement has the disadvantage that the slot in the bottom cover and receiving the tops of the cartons does not in practice always have a continuous, smooth outward flow of air, but various suction and other effects, caused by external draughts, carton movement, etc. result in air flowing inwards through the slot and thus carrying in bacteria from outside.
[0004] Swiss Patent 197802 discloses the use of bactericidal radiation either in the form of an electron beam or in the form of ultra-violet radiation at an aseptic treatment station occupying only a small part of the length of the container path. Thus, again there is the disadvantage that, if sufficient sterilization is to be obtained, the speed of advance of the containers, and thus the rate of production of the machine, is undesirably limited.
[0005] According to a first aspect of the present invention, there is provided an aseptic packaging method, comprising introducing containers into an aseptic chamber . of an aseptic packaging machine of elongate form; conveying said containers along a path in said chamber including both an advance leg and a return leg each extending along the machine ; sterilizing the interiors of said containers to render said interiors aseptic, feeding a product into said containers and sealingly closing said containers , all while said containers are on said path ; characterised in that said sterilizing comprises irradiating said interiors with bactericidal radiation over at least a major portion of the length of said advance leg.
[0006] According to a second aspect of the present invention, there is provided an aseptic packaging machine of elongate form, comprising an aseptic chamber introducing means arranged to introduce containers into said chamber ; conveying means arranged to convey said containers along a path in said chamber including both an advance leg and a return leg each extending along the machine ; sterilizing means arranged to render aseptic the interiors of said containers while said containers are on said path ; feeding means . arranged to feed a product into said containers while said containers are on said path downstream of said sterilizing means ; and sealing means arranged sealingly to close said containers while said containers are on said path downstream of said feeding means ; characterised in that said sterilizing means comprises bactericidal radiation emitting means extending over a section of said path forming at least a major portion of the length of said advance leg.
[0007] By providing that the sterilization comprises irradiating the interiors with bactericidal radiation over at least a major portion of the advance leg, it is possible to have a relatively high speed of carton conveyance combined with sufficient sterilization of the carton interior.
[0008] According to a third aspect of the present invention, there is provided an aseptic packaging method, comprising introducing into an aseptic chamber , pre-formed, open-topped cartons ; sterilizing the interiors of the cartons to render said interiors aseptic while the cartons are within the chamber ; feeding a product into the cartons while the cartons are within the chamber ; top-sealing the cartons while the cartons are within the chamber ; and removing the product-containing cartons from the chamber ; characterised in that a stream of aseptic air is passed through said chamber in the direction from the product-feeding location to the carton entry of the chamber during said sterilizing, said feeding, and said top-sealing.
[0009] According to a fourth aspect of the present invention, there is provided aseptic packaging apparatus, comprising an aseptic chamber ; introducing and removing means arranged to introduce pre-formed, open-topped cartons into said chamber and to remove product-containing cartons therefrom; sterilizing means arranged to render aseptic the interiors of the open-topped cartons while the cartons are within the chamber ; feeding means . arranged to feed a product into the open-topped cartons while the cartons are within the chamber ; and top-sealing means arranged to seal the tops of the cartons while the cartons are within the chamber , characterised in that means is arranged to pass a stream of aseptic air through said chamber in the direction from said feeding means towards a carton entry of said chamber
[0010] Because the cartons are within the chamber and the air flow is along the chamber from the feeding station to the carton entry, the possibility of bacteria travelling to the feeding location and to the sterilized cartons is considerably reduced.
[0011] In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-
Figure 1 shows a diagrammatic top plan view of an aseptic packaging machine,
Figure 2 shows a diagrammatic side elevation of the machine,
Figure 3 shows a diagrammatic end elevation of the machine in the direction of the arrow III in Figure 2,
Figure 4 shows a sectional plan view of the left-hand end of the machine in Figure 1,
Figure 5 shows a sectional end elevation of a top pre-breaking device of the machine,
Figure 6 shows a side elevation of part of a dosaging filling device of the machine,
Figure 7 shows a partly sectional end elevation of that part of the filling device,
Figure 8 shows a sectional side elevation of an expansion device of the filling device,
Figure 9 shows a sectional end elevation of the expansion device, and
Figure 10 shows diagrammatically a modified manner of filling a carton by means of the filling device.
[0012] Referring to the drawings, the machine 1 for carrying out aseptic packaging includes at one end of the machine a conventional device 2 for pre-forming (including bottom-sealing) gable-topped cartons. The open-topped, pre-formed cartons are taken to the other end of the machine through a closed channel 3 by means of a chain system. The channel 3 is bounded by covers 4 individually liftable about hinges to give access to the channel interior. At this front end of the machine, the open-topped cartons are advanced stepwise and in a vertically upright condition by means of conveying chains 5 along a hairpin-shaped path P of which an advance leg extends along the machine towards the device 2 and a return leg extends along the machine 1 back towards its front end. The cartons exit from the channel 3 directly into an aseptic chamber 6 which totally encloses the chains 5 and which is provided with access covers 6"'. The chains 5, which are arranged coextensively one above another, have projecting therefrom outwardly of the path P long lugs 5' which extend beyond guide strips extending along the path P, the cartons being received among and advanced along the path P by the long lugs 5' and being supported at one side by the chains 5 and at the other side by the guide strips. The chains 5 carry the cartons first of all to a top pre-breaking device 7, where the open top of each carton is pre- broken. Then the cartons are passed beneath high-intensity ultra-violet germicidal lamps 8 which extend over a section of the hairpin-shaped path P which forms at least a major portion, in the present case in fact a major portion, of the length of the advance leg of the path P. In the region of the beginning of this section of the path P, there is arranged some means for introducing into the interior of the carton a fine spray of hydrogen peroxide (H2O2). This means comprises a nozzle arrangement 7' incorporated in the pre-breaker 7 and serving to spray particularly the inside of the carton with H202. The combined effect on the interiors of the cartons of the ultraviolet radiation and the hydrogen peroxide has a synergistic sterilizing action which is highly germicidal. Where the degree of sterilisation required is not very great, it is possible to omit use of hydrogen peroxide. At the downstream end of this path section, the chains 5 carry the cartons round through 180° to start the return leg of the path P. On this leg, the cartons first arrive at a filling device 9 where the cartons are filled with an aseptic product, for example long-life milk, the cartons then proceeding to a top heating device 10 where thermoplastics surfaces of the top of each carton are heated to a tacky condition, and the cartons are then advanced to a top sealing device 11 where the gable tops are sealed. The cartons leave the aseptic chamber 6 at an exit hole 6" therefrom at the front end of the machine. Throughout the operation of the machine, aseptic air is fed from a main sterile air filter to aseptic air inlets 13 and 13' of the chamber 6, in which chamber the aseptic air flows from the inlet 13 relatively smoothly to the front end of the chamber 6, where the aseptic air leaves via an aseptic air outlet 14. Not only does the aseptic air act as a scavenging gas removing microbes and hydrogen peroxide from the chamber 6, particularly tending to prevent the microbes and the hydrogen peroxide from being carried up to the filling device 9, but the aseptic air also maintains the interior of the chamber 6 at a pressure slightly above atmospheric and thus discourages the entry of ambient air into the chamber.
[0013] Referring particularly to Figures 4 and 5, the top pre-breaker 7 is in two sections 71 and 72 which are carried by a common horizontal support 73 itself carried by two horizontal arms 74 fixed to a vertically reciprocating plunger 75. The section 71 comprises two substantially triangular flaps 76 turnable about respective substantially horizontal parallel pivots 77 by respective oscillatory cranks 78. Betueen.each two advances of the stepwise-advanced cartons, the pre-breaking device 7 is lowered onto the two cartons beneath it, and performs its pre-breaking and simultaneously the H202 is sprayed into the carton immediately beyond the section 72 by the nozzle device 7'.
[0014] The filling device 9 is particularly designed to prevent microbes obtaining access to the aseptic liquid product being supplied to the chamber 6. Referring to Figures 6 to 9, the filling device includes a mounting frame 20 which mounts four stainless steel reciprocatory bellows 21 having bottom walls which are reci- procatorily driven by respective reciprocatory plungers 22 and having top flanges fixed to respective lower limbs of T-unions 23. Respective upper limbs of the unions 23 contain respective spring-loaded, non-return, inlet valves which open to allow downward flow through the linbs. Intermediate limbs of the respective unions 23 are connected to respective arcuate pipes 24 which curve downwardly and which at their lower ends are connected to respective outlet nozzles 25 which contain respective spring-loaded, non-return, outlet valves. The chains 5 advance the cartons stepwise directly below the line of nozzles 25 and a selected number of the bellows 21 are operated each to deliver a predetermined dosage of long-life milk to.the vertically upright cartons, the number of bellows 21 operated being dependent upon the nominal capacity of the cartons. Thus, with each bellows 21 being pre-set to deliver a halfpint at each reciprocation, all four bellous 21 are operated for cartons which can each hold one quart. On each bellows 21 performing a pressure stroke, because the inlet valve in its union 23 is held closed by its spring and by the milk pressure, the inlet valve is automatically opened against the action of its spring so that the bellows 21 can draw in milk from an expansion device 26 shown in Figures 8 and 9: The device 26 is connected to the upper limbs of all of the T-unions 23 by way of its outlet 27. A pump (not shown) continuously pumps long-life milk into the device 26 through its inlet 28. The interior of the device 26 is divided into an expansion chamber 29 and a constant-pressure chamber 30 by an annular bellows 31 and a rigid, movable, end closure wall 32 thereof. The chamber 30 is set at a substantially constant pressure owing to the provision of a pressure-regulated air supply to the chamber 30 via a port 33 in a removable end wall 34 of the device 26. There extends through the wall 34 in a fluid-tight manner a rod 35 which is fixed at one end to the plate 32. The. rod 35 carries abutment flanges 36 which limit the degree of movement of the vall 32 relative to the wall 34. The rod 35 also carries a pointer 37 which moves over a scale 38 to indicate the position of the wall 32 in the device 26. In use of the machine, when the instantaneous rate of delivery of the pump to the inlet 28 exceeds the rate of drawing of the milk into the bellows 21 via the outlet 27, the wall 32 is moved by the pressure of the milk to the right in Figure 9 against the action of the air pressure in the chamber 30, so that the expansion device 26 acts temporarily as a reservoir until the rate of drawing of the milk into the bellows 21 exceeds the rate of delivery by the pump, in which case the plate 32 moves to the left in Figure 9 under the action of the air pressure in the chamber 30. It will thus be appreciated that, at least between the pump (not shown) and the outlet valves in the nozzles 25, the filling system is always absolutely full of long-life milk, so that there are no voids or air spaces, which would possibly allow microbes to obtain access to the milk. Another advantage of the present filling system is that all of the internal surface area of the system which in use is in contact with the long-life milk can itself easily be sterilised by simply passing a very hot liquid, chemical cleaning fluid or steam through the filling system, so that all of that internal surface area comes into contact with the very hot liquid, the fluid, or the steam.
[0015] Referring to Figure 10, a carton C is shown being filled from one of the nozzles 25. It will be noted that, in this modified manner of filling, the carton C is in a position inclined to the vertical, so that the milk flowing from the nozzle 25 falls dovn onto an internal face of the carton C which face is inclined to the vertical and is directly below the nozzle 25. Compared to a conventional arrangement in which a nozzle pours milk down into a carton arranged in a substantially exactly upright position directly below the nozzle and thus the milk leaving the nozzle virtually always pours directly onto a body of milk in the carton, the arrangement shown in Figure 10 has the advantage of minimising the production of foam on the top of the milk. In the present case, the cartons C move along the path P in upright positions, except in the region of the filling device 9, where they are in a tilted condition. It will be appreciated that movement of the carton from its upright condition to its tilted condition and then back to its upright condition can be produced in various ways, particularly by suitable design of the chains 5 and/or the guide'strips for the cartons.
[0016] The machine 1 also includes automatically controlled means for cleaning the internal surface of the aseptic chamber 6, this means consisting of spray nozzles 41 distributed centrally along the length of the chamber. These nozzles serve to supply a cleaning fluid, e.g. a hot detergent solution or steam, to the interior of the chamber 6 in such a manner that the whole of the interior of the chamber 6 receives the cleaning fluid, which can then be drained off through a drain (not shown).
[0017] The machine 1, particularly the aseptic chamber 6 and the associated machine parts, such as the items 5 to 11, are so designed that the only non-aseptic matter deliberately introduced into the chamber 6 is the preformed cartons C.
[0018] The entry 3' where the empty cartons enter theaseptic chamber 6 and the exit 6" where the filled cartons leave the aseptic chamber can be sealed off outside the chamber 6 by respective air curtains of aseptic air at higher pressure. Thus the lower-pressure aseptic air inside the chamber 6 is prevented from escaping. These air curtains are established by slotted tubes 81 and 82 seen in Figures 4 and 3, respectively. The aseptic air for the curtains is taken from a separate sterile air filter giving higher pressure than the main sterile air filter for the chamber 6 itself.
1. An aseptic packaging method, comprising introducing containers (C) into an aseptic
chamber (6) of an aseptic packaging machine (1) of elongate form; conveying said containers
(C) along a path (P) in said chamber (6) including both an advance leg and a return
leg each extending along the machine (1); sterilizing the interiors of said containers
(C) to render said interiors aseptic, feeding a product into said containers (C) and
sealingly closing said containers (C), all while said containers (C) are on said path
(P); characterised in that said sterilizing comprises irradiating said interiors with
bactericidal radiation over at least a major portion of the length of said advance
leg.
2. A method according to claim 1, characterised in that said sterilizing comprises
producing in said interiors a synergistic sterilizing effect by spraying said interiors
with hydrogen peroxide and irradiating the sprayed hydrogen peroxide with said radiation
in the form of ultra-violet radiation.
3.' A method according to claim 2, wherein said containers (C) are cartons (C), characterised
in that said spraying is performed at a top pre-breaking station (7) on said path
(P).
4. An aseptic packaging machine of elongate form, comprising an aseptic chamber (6);
introducing means (3) arranged to introduce containers (C) into said chamber (6);
conveying means (5) arranged to convey said containers (C) along a path (P) in said
chamber (6) including both an advance leg and a return leg each extending along the
machine (1); sterilizing means (7', 8) arranged to render aseptic the interiors of
said containers (C) while said containers (C) are on said path (P); feeding means
(9) arranged to feed a product into said containers (C) while said containers (C)
are on said path (P) downstream of said sterilizing means (7', 8); and sealing means
(11) arranged sealingly to close said containers (C) while said containers (C) are
on said path (P) downstream of said feeding means (9); characterised in that said
sterilizing means (7', 8) comprises bactericidal radiation emitting means (8) extending
over a section of said path (8) forming at least a major portion of the length of
said advance leg.
5. A machine according to claim 4, characterized in that said sterilizing means (7',
8) comprises both said bactericidal radiation emitting means (8) in the form of ultra-violet
radiating means (8) and spraying nozzle means (7') for spraying said interiors with
hydrogen peroxide.
6. A machine according to claim 5, and further comprising a top pre-breaking means
(7) situated in the region of the beginning of said advance leg for pre-breaking top
closures of said containers (C), characterised in that said spraying nozzle (7') is
carried by the top pre-breaking means (7).
7. An aseptic packaging method, comprising introducing into an aseptic chamber (6)
pre-formed, open-topped cartons (C); sterilizing the interiors of the cartons (C)
to render said interiors aseptic while the cartons (C) are within the chamber (6);
feeding a product into the cartons (C) while the cartons (C) are within the chamber
(6); top-sealing the cartons (C) while the cartons (C) are within the chamber (6);
and removing the product-containing cartons (C) from the chamber (6); characterised
in that a stream of aseptic air is passed through said chamber (6) in the direction
from the product-feeding location (9) to the carton entry (3') of the chamber during
said sterilizing, said feeding, and said top-sealing.
8. Aseptic packaging apparatus, comprising an aseptic chamber (6); introducing and
removing means (3, 3', 6") arranged to introduce pre-formed, open-topped cartons (C)
into said chamber (6) and to remove product-containing cartons (C) therefrom, sterilizing
means (7', 8) arranged to render aseptic the interiors of the open-topped cartons
(C) while the cartons (C) are within the chamber (6); feeding means (9) arranged to
feed a product into the open-topped cartons (C) while the cartons (C) are within the
chamber (6); and top-sealing means (11) arranged to seal the tops of the cartons (C)
while the cartons (C) are within the chamber (6), characterised in that means (13,
13') is arranged to pass a stream of aseptic air through said chamber (6) in the direction
from said feeding means (9) towards a carton entry (3') of said chamber (6).