US 3486295 A
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Des. 30, 1969 a. A. RAUSING ET AL 3,486,295
METHOD OF PACKAGING STERILE LIQUIDS Filed Feb. 13, 1967 s w mm m Pm w n RQ mm fi n Amw m OIL a m G W V, B
United States Patent 3,486,295 METHOD OF PACKAGING STERILE LIQUIDS Gad Anders Rausing, Lund, and Alex Tuma, Loddekopinge, Sweden, assignors to AB Tetra Pak, Lund, Sweden, a company of Sweden Filed Feb. 13, 1967, Ser. No. 615,827 Claims priority, application Sweden, Mar. 7, 1966, 2,921/ 66 Int. Cl. 1365b 31/02 lU.S. C]. 53-89 2 Claims ABSTRACT OF THE DISCLOSURE A method and device for filling a receptacle under sterilised conditions comprises a chamber into which an unsterilised open top container is inserted. The chamber is thereafter sealed closed, a sterilising agent is admitted into the chamber to sterilise both it and the interior of the container, the filling liquid is then introduced into the container after which the container top is pressed closed, and the filled and closed container is then removed subsequent to re-opening of the chamber.
The present invention is a method of packaging sterile substances and especially sterile liquids in a container, preferably a container of a type which has a wide opening.
There exists a need for packaging sterile liquids, e.g. sterile milk, in cheap packages of the throw-away type. It was certainly possible before to package sterilised liquids in e.g. bottles or tins which before being filled had been sterilised by means of heating or treatment with a chemical sterilising agent. These known methods and known packaging equipment are however not suitable for the treatment of materials that are comparatively sensitive to heat, such as paper, plastic, or combinations of these, since the known methods usually work on the principle of the substance being first packed in airtight packages and then, together with its package, being heated to sterilising temperature. Packages are also produced by means of sealing and subdividing internally sterile tubes after these have been filled with a sterile substance.
In containers which are not produced from a tube but from a piece of material manufactured in advance, it has proved diificult to sterilise the containers in a rational manner before the introduction of the contents. This problem has been solved by means of the method in accordance with the invention, which is characterised by a packaging container produced in advance being inserted into a sterilising chamber which is so arranged as to receive such a container, the chamber being thereafter provided with a germ-tight seal; by a sterilising agent in the form of a gas or vapour being made to flow into and through the chamber and thereby to sterilise the chamber and the equipment ancillary thereto as well as the container introduced into the chamber; by a sterile substance being introduced into the container by means of a filler nozzle fitted to the chamber, after both the chamber and the container have been sterilised; and by the container being provided with a germ-tight seal and taken out of the chamber, which thereafter is ready to receive a new container to be filled up.
In order to carry out the method in accordance with the invention, there is provided equipment characterized by a germ-tight chamber which is provided with a filler nozzle connected to a store of the sterile substance, with fittings for the supply of the sterilising agent and the removal of the sterilising agent that has fiown through the chamber, and with mechanism for the closing of the container or containers in the chamber.
An especially advantageous form of the invention will now be described with reference to the attached diagrammatical drawing, on which FIG. 1 shows how an empty container is introduced into a sterilising chamber,
FIG. 2 shows the sterilisation of the chamber and the container,
FIG. 3 shows the filling of the container,
FIG. 4 shows the closing of the container and finally FIG. 5 shows how the package is taken out of the sterilising chamber and is finally sealed.
The sterilising chamber 16 which is shown in FIGS. 1-5 consists in the type demonstrated of the interior of a housing 1 open at the bottom, into which are connected a duct 6 for the supply of the sterilising agent, and exhaust duct 12, a filler nozzle 10, a vacuum pipe 11 and the mechanism 14 for closing the full containers. Ducts 6 and 12 are both provided with valves 8 and 13 by means of which the flow of the sterilising agent into and out of chamber 16 may be regulated.
The sterilising chamber is closed with a bottom plate 3 which by means of a rod 4 may be moved to any one of two positions. The bottom 3 is brought over the opening of chamber 16 and pressed against a gasket type seal 5. The bottom 3 which in one of the positions is thus an end-wall of the sterilising housing 1 is arranged to serve as a platform for the container 2 to be sterilised and filled.
The different stages of the sterilising and packaging operations are shown in FIGS. 1S, where FIG. 1 shows an empty pre-produced packaging container which in the form of the invention considered is to be a plastic coated paper or carton container of the type which is closed by means of concertina folding of the upper edge portion of the container. The container 2 is placed on bottom 3 and is pushed by means of rod 4 into the sterilising chamber 16.
When the bottom has reached the lower edge of the sterilising housing 1, a germ-tight seal is obtained by means of the sealing gasket 5 between the lower portion of the sterilising housing 1 and the bottom 3.
During the whole of the sequence described, valves 8 and 13 as well as filling pipe 10 and vacuum pipe 11 have been closed.
When sterilising housing 1 is closed, that is to say when the position shown in FIG. 2 has been reached, valves 8 and 13 are opened. Through duct 9, which is connected to a store of the sterilising agent or an apparatus producing the sterilising agent, in this case steam, the steam heated to sterilising temperature flows into sterilising chamber 16. In order that both the sterilising chamber 16 and the equipment therein as Well as the container 2 should be sterilised in the most eflicient way possible, the discharge end of supply pipe 6 is constructed with dual discharge nozzles 7a, 7b such that the inside of the container has a direct supply of steam through nozzle 7a while the exterior of the container is bathed with the sterilising agent through nozzle 7b. Thus the inside and outside of container 2 may be simultaneously treated as the rest of the sterilising chamber is sterilised.
The steam temperature during experiments was C. (300 F.) and the effective time approximately 5 seconds.
The valve 13 is open during the time steam flows through, in order that this may leave the sterilising chamber.
When the sterilising chamber 16 with its contents has been sterilised, valves 8 and 13 are shut. Valve 13 is shut in order to prevent contaminated air being sucked back into duct 12, since the steam in the sterilising chamber 16 condenses and there is thus a lower pressure in the chamber. Valve 13 may perhaps be shut a little later than valve 8 but no later than when the pressure in sterilising chamber 16 has decreased so much that the inner and outer pressures are equal.
In order that it should be possible to heat the sterilising chamber quickly to sterilising temperature, valve 13 may be opened after valve 8. If the steam entering has a sufficiently high temperature, sterilising temperature may be reached in the sterilising chamber without steam being exhausted during the whole of the time that valve 8 is open. This is naturally preferable from the point of view of steam economy.
If so desired, part of the steam in the container may, before it condenses, be sucked out through the vacuum pipe 11 which is connected to a vacuum pump.
This evacuation of the steam certainly reduces the quantity of condensate in the container, but since this quantity is very little this does not seem to have any significance. Should the sterilising agent, however, be a chemical sterilising gas, e.g. ethylene dioxide, it may be necessary to evacuate the gas and perhaps replace it by sterilised air before the filling operation.
FIG. 3 shows how the sterilised container 2 is filled with the sterile substance through filler nozzle connected to a storage container for the substance. In order to prevent splashing and frothing, filler nozzle 10 is made retractable so that at the beginning of the filling operation it may reach right down into the container and then during filling be gradually drawn up with the orifice below the surface of the contents, so that after filling has been completed it may reach a position above the upper edge of the container 2.
After completion of the filling operation, container 2 is closed by reciprocating rod mechanism which comprises a pair of mating pressure jaws 14 located at the inner ends of the rods.
The closure which naturally may be effected in many ways should be so mechanically durable that it will not become undone when the package is removed from sterilising chamber 16 in the manner shown in FIG. 5. The removal of the closed container 2 from sterilising chamber 16 is effected by means of rod 4 which is displaced downwards.
The sterility of sterilising chamber 16 as well as the outside of container 2 is naturally lost when sterilising chamber 16 is opened, but owing to the closure of the container 2 being germ-tight both the inside of container 2 and the contents are protected from contamination. In order to obtain a durable seal, it is best to heat-seal the container by means of a pair of sealing jaws arranged outside the sterilising housing 1, when container 2 has been removed from sterilising chamber 16.
The finished package is removed from the bottom 3 on which is then placed a new, empty container 2 which is introduced into sterilising chamber 16, whereupon the whole cycle of operations is repeated.
It is naturally possible to modify, within the framework of the idea underlying the invention, the method as well as the equipment for carrying out the method. Thus sterilising housing 1 may with advantage be constructed so large that a number of containers can be treated at the same time, and further, as mentioned earlier, it is not necessary to use steam, either dry or superheated, as the sterilising agent but it is possible to make use of a number of other heat carriers heated up to sterilising temperature, and also chemically sterilising gases or vapours. The method may further naturally be used on types of packaging containers other than those consisting of plastic-coated paper or cardboard, even if the method is especially suitable for this type of container, since it had not earlier been possible to sterilise and fill these by known methods. In order that treatment time during sterilisation may be reduced, it is best that the container should have a comparatively wide opening, which will assist efiicient flow of the steam; otherwise the packaging container may have any shape.
The method has proved simple and reliable and comparatively cheap when used with the equipment shown, since the quantity of steam consumed in sterilisation is slight and the sterilising process fast and efiicient.
1. A device for filling a plastic coated container with a sterile liquid comprising a housing having an open bottom which faces downwardly, a support plate on which an open top container is carried, means for raising said support plate upwardly from a starting position into contact with the side walls of said housing thereby to close off the interior of said housing to establish a filling chamber and carry said container into the same, supply and removal pipe means for flowing a gaseous sterilising agent in the form of steam into and out of said chamber. cut-01f valves located respectively in said supply and removal pipe means, means for evacuating said chamber. a filling pipe in said chamber for filling said open top container, said filling pipe being movable longitudinally of itself so as to enter and be withdrawn from said container, and means for closing the top of said container while in said chamber and subsequent to the filling thereof, said support plate being thereafter lowered to its starting position to open said chamber and withdraw said filled and closed container, the surfaces of said means for closing the top said container and the interior surface of said support plate which come into contact with the plastic coated surface of said container being provided with an adhesion preventative coating.
2. A device for filling a container as defined in claim 1 wherein said means for closing the top of said container is comprised of a pair of longitudinally movable jaws adapted to be brought into pressure contact with the walls of the container which define its top opening, and wherein said filling pipe is movable longitudinally of itself to enter and be withdrawn from the top opening of said container, said filling pipe when in its withdrawn position being located at a level above said top closing jaws.
References Cited UNITED STATES PATENTS 3,177,906 4/1965 Meyer-Jagenberg 14l374 3,220,157 11/1965 Buchner 5395 2,796,913 6/1957 Fener et al. 1,365,673 1/1921 Penn 53ll FOREIGN PATENTS 607,465 10/1960 Canada.
THERON E. CONDON, Primary Examiner H. M. CULVER, Assistant Examiner US. Cl. X.R.