EP0013132B1 - Apparatus comprising a dosaging device for a liquid product and a method for it - Google Patents

Description

• This invention relates to apparatus comprising a dosaging device arranged to deliver a liquid product in predetermined individual doses, particularly in the aseptic packaging of liquid products, for example long-life milk, in cartons.
• Filling stations of machines for automatically opening-out, filling, closing and sealing cartons are of various forms, for example those disclosed in United States Patents 2,841,936 and 3,352,458.
• United States Patent 2841936 discloses such a machine in which the filling mechanism comprises a tank having a discharge nozzle and a normally closed valve which controls the flow of liquid through the nozzle, which valve is operated to its open position by a solenoid and is retained in its open position as long as the solenoid remains energized. A float controlled mechanism is provided in the tank to control the admittance of fluid thereinto and is arranged to maintain a substantially constant level in the tank so as thereby to provide a controlled rate of discharge through the nozzle.
• United States Patent 3,352,458 discloses another such machine, whereof the filler unit has a circular delivery tank provided with an inlet and a pair of outlets spaced from each other lengthwise of the carton track so that each will overlie the open mouth of a carton in both of its positions in which it is stopped under the filler unit. Each outlet has an internal seat for an outlet valve and a depending nozzle provided with a cap connected thereto as by a bayonet type of joint and having outlet ports disposed to provide for a desired flow therethrough in a manner minimizing foaming. The caps may be removed and replaced by others providing for a different volumetric flow or one may be replaced by a shutoff cap to block all flow through the outlet to the nozzle to which it is attached.
• Each valve is adapted to be closed and held closed by an electro-magnet against the action of a float, with each float having vertically aligned upper and lower rods connected thereto. Each lower rod is connected to its valve and each upper rod includes a part functioning as the core of a valve-operating electro-magnet.
• A surge tank has an inlet which is horizontal as an aid against foaming, from a source such as a pasteurizer or homogenizer, for example, and controlled by a float valve, and an outlet connected to the inlet of the delivery tank by a valve.
• Whenever a carton is under an outlet of the filler unit, the electro-magnets in control of the outlet valves are de-energized for the interval determined by a timing relay. If there is then a sufficient body of liquid in the delivery tank the outlet valves open and stay open until the electro-magnets are again energized or until the liquid level in the tank drops sufficiently.
• The known filling stations have the disadvantage that during use they contain, in contact with the liquid, voids or air spaces, which allow microbes to obtain access to the liquid.
• British Patent Specification No. 1335007 discloses a metering device for filling packaging containers with liquids and pastes, comprising at least one unit having an inlet valve connected to a feed line and an outlet valve which is connected by a bellows of polytetrafluoroethylene, for example, to the inlet valve and which has a valve body in the form of a diaphragm carrying an outlet nozzle, the two ends of the bellows of the or each unit being clamped to two spaced horizontal plates which are relatively movable through an adjustable distance, there being some means to open the inlet valve when the plates are moving apart and to close the inlet valve when the plates are moving together, the outlet valve being arranged to open when the plates are moving together and to close when the plates are moving apart. The inlet valve can consist of a stem extending through the wall of ducting leading to the bellows and provided at its end within the ducting with a frusto-conical valve plate which co-operates with a similarly shaped valve seat formed by an internal shoulder of the ducting. The diaphragm of the outlet valve can be arranged to be held in a closed position by compressed air introduced around the nozzle and beneath the diaphragm. However, the diaphragm of the outlet valve may instead be prestressed so that it is bent upwardly and not downwardly when it is relaxed. In this instance, it is possible to dispense with the compressed air control, since the outlet valve is always in the closed position except when the lower plate is being moved upwardly. However, in the latter circumstance, i.e. when the bellows is being compressed, the pressure of the liquid in the bellows overcomes the prestress of the diaphragm, so that the outlet valve opens and allows the liquid to escape. However, such an arrangement has the disadvantage of lesser operational reliability than that utilizing compressed air control. The inlet valve, which is angled, may be replaced by a vertical axis valve which, if required, may also be provided with a pneumatic control arrangement.
• According to the present invention, there is provided apparatus comprising a dosaging device arranged to deliver a liquid product in predetermined individual doses, a pumping device arranged to deliver continuously said product under pressure, and a chamber by way of which said pumping device communicates with said dosaging device and whereof the volume of said product therein varies in dependence on the difference between the rates of flow of said product there-into and therefrom, characterised in that said chamber has a flexible wall part whereby the volume of said chamber varies with said volume of said product.
• Owing to the invention, it is possible to avoid the presence in the apparatus of voids or air spaces in contact with the liquid product during use of the apparatus.
• 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.
• Referring to the drawings, themachine 1 for carrying out aseptic packaging includes at one end of the machine aconventional 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 closedchannel 3 by means of a chain system. Thechannel 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 conveyingchains 5 along a hairpin-shaped path P of which an advance leg extends along the machine towards thedevice 2 and a return leg extends along themachine 1 back towards its front end. The cartons exit from thechannel 3 directly into anaseptic chamber 6 which totally encloses thechains 5 and which is provided with access covers 6"'. Thechains 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 thechains 5 and at the other side by the guide strips. Thechains 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 ultravioletgermicidal 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 (H₂0₂). This means comprises a nozzle arrangement 7' incorporated in the pre-breaker 7 and serving to spray particularly the inside of the carton withH₂0₂. 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, thechains 5 carry the cartons round through 180° to start the return leg of the path P. On this leg, the cartons first arrive at afilling device 9 where the cartons are filled with an aseptic product, for example long-life milk, the cartons then proceeding to atop 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 atop sealing device 11 where the gable tops are sealed. The carbons leave theaseptic chamber 6 at anexit 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 toaseptic air inlets 13 and 13' of thechamber 6, in which chamber the aseptic air flows from theinlet 13 relatively smoothly to the front end of thechamber 6, where the aseptic air leaves via anaseptic air outlet 14. Not only does the aseptic air act as a scavenging gas removing microbes and hydrogen peroxide from thechamber 6, particularly tending to prevent the microbes and the hydrogen peroxide from being carried up to thefilling device 9, but the aseptic air also maintains the interior of thechamber 6 at a pressure slightly above atmospheric and thus discourages the entry of ambient air into the chamber.
• Referring particularly to Figures 4 and 5, the top pre-breaker 7 is in twosections 71 and 72 which are carried by a commonhorizontal support 73 itself carried by twohorizontal arms 74 fixed to a verticallyreciprocating plunger 75. Thesection 71 comprises two substantiallytriangular flaps 76 turnable about respective substantially horizontalparallel pivots 77 by respectiveoscillatory cranks 78. Between 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 theH₂0₂ is sprayed into the carton immediately beyond thesection 72 by the nozzle device 7'.
• Thefilling device 9 is particularly designed to prevent microbes obtaining access to the aseptic liquid product being supplied to thechamber 6. Referring to Figures 6 to 9, the filling device includes amounting frame 20 which mounts four stainless steelreciprocatory bellows 21 having bottom walls which are reci- procatorily driven byrespective reciprocatory plungers 22 and having top flanges fixed to respective lower limbs of T-unions 23. Respective upper limbs of theunions 23 contain respective spring-loaded, non-return, inlet valves which open to allow downward flow through the limbs. Intermediate limbs of therespective unions 23 are connected to respectivearcuate pipes 24 which curve downwardly and which at their lower ends are connected torespective outlet nozzles 25 which contain respective spring-loaded, non-return, outlet valves. Thechains 5 advance the cartons stepwise directly below the line ofnozzles 25 and a selected number of thebellows 21 are operated each to deliver a predetermined dosage of long-life milk to the vertically upright cartons, the number ofbellows 21 operated being dependent upon the nominal capacity of the cartons. Thus, with eachbellows 21 being preset to deliver a halfpint at each reciprocation, all fourbellows 21 are operated for cartons which can each hold one quart. On eachbellows 21 performing a pressure stroke, because the inlet valve in itsunion 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 thebellows 21 can draw in milk from anexpansion device 26 shown in Figures 8 and 9. Thedevice 26 is connected to the upper limbs of all of the T-unions 23 by way of itsoutlet 27. A pump (not shown) continuously pumps long-life milk into thedevice 26 through itsinlet 28. The interior of thedevice 26 is divided into anexpansion chamber 29 and a constant-pressure chamber 30 by anannular bellows 31 and a rigid, movable,end closure wall 32 thereof. Thechamber 30 is set at a substantially constant pressure owing to the provision of a pressure- regulated air supply to thechamber 30 via aport 33 in aremovable end wall 34 of thedevice 26. There extends through thewall 34 in a fluid-tight manner arod 35 which is fixed at one end to theplate 32. Therod 35 carriesabutment flanges 36 which limit the degree of movement of thewall 32 relative to thewall 34. Therod 35 also carries apointer 37 which moves over ascale 38 to indicate the position of thewall 32 in thedevice 26. In use of the machine, when the instantaneous rate of delivery of the pump to theinlet 28 exceeds the rate of drawing of the milk into thebellows 21 via theoutlet 27, thewall 32 is moved by the pressure of the milk to the right in Figure 9 against the action of the air pressure in thechamber 30, so that theexpansion device 26 acts temporarily as a reservoir until the rate of drawing of the milk into thebellows 21 exceeds the rate of delivery by the pump, in which case theplate 32 moves to the left in Figure 9 under the action of the air pressure in thechamber 30. It will thus be appreciated that, at least between the pump (not shown) and the outlet valves in thenozzles 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 is 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.
• Referring to Figure 10, a carton C is shown being filled from one of thenozzles 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 thenozzle 25 falls down onto an internal face of the carton C which face is inclined to the vertical and is directly below thenozzle 25. Comared 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 thefilling 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 thechains 5 and/or the guide strips for the cartons.
• Themachine 1 also includes automatically controlled means for cleaning the internal surface of theaseptic chamber 6, this means consisting ofspray 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 thechamber 6 in such a manner that the whole of the interior of thechamber 6 receives the cleaning fluid, which can then be drained off through a drain (not shown).
• Themachine 1, particularly theaseptic chamber 6 and the associated machine parts, such as theitems 5 to 11, are so designed that the only non-aseptic matter deliberately introduced into thechamber 6 is the preformed cartons C.
• The entry 3' where the empty cartons enter theaseptic chamber 6 and theexit 6" where the filled cartons leave the aseptic chamber can be sealed off outside thechamber 6 by respective air curtains of aseptic air at higher pressure. Thus the lower-pressure aseptic air inside thechamber 6 is prevented from escaping. These air curtains are established by slottedtubes 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 thechamber 6 itself.

Claims (10)

1. Apparatus comprising a dosaging device (21-25) arranged to deliver a liquid product in predetermined individual doses, a pumping device arranged to deliver continuously said product under pressure, and a chamber (29) by way of which said pumping device communicates with said dosaging device (21-25) and whereof the volume of said product therein varies in dependence on the difference between the rates of flow of said product there- into and therefrom, characterised in that said chamber (29) has a flexible wall part (31) whereby the volume of said chamber (29) varies with said volume of said product.

2. Apparatus according to claim 1, characterised in that force-applying means (30, 33) is arranged to apply to said flexible wall part (31) a force which is of a substantially constant value.

3. Apparatus accoridng to claim 2, characterised in that said force-applying means (30, 33) comprises a constant-pressure chamber (30) and supply means (33) arranged to supply a pressure fluid to said constant-pressure chamber (30) to maintain a substantially constant pressure therein.

4. Apparatus according to any preceding claim, characterised in that indicating means (37) is connected to said flexible wall part (31) and arranged to indicate the position thereof.

5. Apparatus according to any preceding claim, characterised in that said flexible wall part (31) comprises an annular bellows (31) sealingly connecting a movable wall part (32) to a fixed wall part of said chamber (29).

6. Apparatus according to any preceding claim and further 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; sterilizing means (7', 8) arranged to render aseptic the interiors of said containers (C) while said containers (C) are on said path (P); said dosaging device (21-25) being arranged to feed said 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 dosaging devices (21-25); characterised in that said sterilizing means (7', 8) comprises bactericidal radiation emitting means (8) extending over a section of said path (P) forming at least a major portion of the length of said advance leg.

7. Apparatus according to claim 6, characterised in that said sterilizing means (7', 8) comprises both said bactericidal radiation emitting means (8) in the form of ultraviolet radiating means (8), and spraying nozzle means (7') for spraying said interiors with hydrogen peroxide.

8. A machine according to claim 7, 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 means (7') is carried by the top pre-breaking means (7).

9. Apparatus according to any one of claims 1 to 5 and further 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 in the chamber (6); said dosaging device (21-25) being arranged to feed said product into the open-topped cartons (C) while the cartons (C) are in the chamber (6); and top-sealing means (11) arranged to seal the tops of the cartons (C) while the cartons (C) are in 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 dosaging device (21-25) towards a carton entry (3') of said chamber (6).

10. A method comprising feeding a liquid product under pressure to a chamber (29) and intermittently applying additional pressure to liquid exiting the chamber (29) to intermittently deliver said liquid product in predetermined individual doses, characterized in that the volume of the chamber (29) is varied in response to the difference between the rate of flow of said product into the chamber (29) and the rate of flow of said product from the chamber (29) to maintain a substantially constant liquid pressure in said chamber (29) with complete liquid contact on all internal surfaces of said chamber (29).

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