Apparatus For Sterilising The Outside Of The Filling Pipe In An Aseptic Packaging Machine

Abstract

Apparatus and method for sterilising the outside of the filling pipe in an aseptic packaging machine, in which the filling pipe projects into the interior of a flexible tube being formed continuously from packaging material in web form, in which the filling pipe is provided with a receiver dish for a vaporisable, chemically acting sterilising liquid at its end, with supply and distribution means for said liquid located around the periphery and above the end of the filling pipe and with means for vaporising the sterilising liquid.

Description

The invention relates to a method and to an apparatus for sterilising the outside of the filling pipe in an aseptic packaging machine. As a rule such machines possess a sterile space which may be formed by a fixed chamber or by the packaging material itself formed into a flexible tube. The filling pipe is in the interior of a sterile space; where the sterile space is formed by the packaging material itself the filling pipe projects into the pre-formed flexible tube. In either case the outside of the filling pipe must be free from organisms during operation or be subjected to a preliminary sterilisation in order to reach this state.

However, it is not an easy matter to effect a satisfactory preliminary sterilisation of the outside of the filling pipe, especially in packaging machines of the type in which the filling pipe projects into the interior of a flexible tube being continuously formed from packaging material in web form. For example, it has already been proposed to introduce hot steam or hot air into the interior of the flexible tube or into the interior of the aforesaid sterile space in order to heat the outside of the filling pipe to the sterilising temperature. However, when hot steam is used condensation forms on the inside of the tube and on the outside of the filling pipe and accumulates at the lower closed end of the flexible tube, preventing the temperature from being brought substantially above the boiling point at atmospheric pressure. Sterilising by thermal means alone would require high temperatures and long exposure times; the packaging material generally consisting of paper, plastics material or the like would not withstand such heating. As a result of damage, the interior of the flexible tube can then easily come into contact with the organism-containing surrounding air to lead to re-infection. This is the case particularly with packages obtained by transverse welding of a flexible tube from a continuously fed web; here the longitudinal welded seam may become detached as a result of the effect of the heat of sterilisation.

The invention makes it possible to substantially eliminate the described drawbacks. In the apparatus in accordance with the invention, the filling pipe projects into the interior of a flexible tube being continuously formed from packaging material in web form and it is characterised in that the filling pipe is provided with a receiver dish for a vaporisable, chemically acting sterilising liquid at its lower end, with supply and distribution means for said liquid located around the periphery and above the lower end of the filling pipe and with means for vaporising the sterilising liquid.

A simple and reliable preliminary sterilising is ensured with the help of the invention and one in which damaging of heat-sensitive packaging material is practically excluded. The chemically acting sterilising liquid applied on to the outside of the filling pipe has a sterilising effect on any organisms present. Flowing downwards, it is collected in the receiver dish and cannot drip on to sensitive parts of the machine. Instead, it is heated in the receiver dish to a temperature adequate to vaporise it by heating. The vapor formed comes into contact with the outside of the filling pipe and, with the inner wall of the flexible tubular packaging material. A reliable sterilising is produced under the combined effect of heat and the chemically acting sterilising agent.

Suitably, the end of the filling pipe may be double walled in such a way that a heating medium can be introduced into the annular space between the outer and inner wall, the heat flowing through the outer wall of the filling pipe into the receiver dish. Such an arrangement also causes the portion of the outside of the filling tube located above the receiver dish to be heated. Furthermore, it may be advantageous under certain circumstances to arrange annular intermediate partitions on the outside of the filling pipe between the point of spraying of the sterilising liquid and the receiver dish which collect the downwardly flowing sterilising liquid and distribute it anew over the periphery of the filling pipe.

In what follows the invention and further associated features and advantages are described in greater detail by way of the examples of embodiments shown in the drawing, in which:

FIG. 1 shows an apparatus in accordance with the invention with a heating annular space for vaporising the sterilising liquid;

FIG. 2 shows the arrangement of intermediate partitions for the sterilising liquid in an arrangement corresponding to FIG. 1; and

FIG. 3 shows an apparatus with a filling pipe containing a movable internal pipe.

The filling pipe illustrated in FIG. 1 has an outer jacket 11 surrounding the feed pipe 12 for the material to be packaged defining an annular space 13. This annular space is closed at the top by the wall 14 and at the bottom by the wall 15. The wall 15 has an extension 16 which forms a receiver dish 17 for collecting sterilising liquid, which liquid can be applied on to the outside surface of the jacket 11 with the aid of multiple means such as nozzles 18 distributed over the periphery of the external jacket 11. The nozzles 18 are connected to a source of a liquid, chemically acting sterilising agent via the line 19. The pipe 20 which terminates (as shown) substantially above the base 15 is placed in the annular space 13 and communicates with a heating medium source, with the heating medium, after flowing through the annular space 13, being discharged through the pipe 21. Hot steam or hot air are recommended heating media; preferably superheated steam at about 120.degree. to 140.degree.C is used. A peroxide solution with a concentration of 20 to 40 percent is particularly suitable sterilising liquid. If desired, the sterilising liquid may be preheated. For the preliminary sterilising of the pipe 12 hot steam or hot air may be introduced into its interior in a not shown manner. The heating obtained and its duration is to be so scheduled that the inside of the pipe 12 is reliably sterilised.

To operate the described apparatus, for example 20 cm.sup.3 of sterilising liquid are sprayed with the aid of the nozzles 18. The liquid flows downwards along the surface of the outside jacket 11 in the manner of a film and is caught in the dish 17. Subsequently the supply of heating medium through the pipe 20 is switched on and the sterilising liquid is evaporated within a period of, for example, 4 minutes. It is possible, alternatively, to switch on the supply of heating medium before supplying the sterilising liquid.

FIG. 2 shows an assembly corresponding to FIG. 1 with external jacket 11, feed pipe 12 and receiver dish 17. Annular intermediate partitions 31 and 32 are located between this dish 17 and the spray nozzles (not shown) for applying the sterilising liquid on to the outside of the jacket 11. The partition 31 collects the film of descending sterilising liquid but distributes it anew with the aid of the holes 33 distributed over the periphery. The sterilising liquid is then caught in a further intermediate partition 32; however, the dish 34 is dimensioned in such a way that only a portion of the total sterilising liquid charged is retained, while the remainder flows downwards over the rim and is finally collected in the receiver dish 17. On supplying heating medium through the pipe 20 the liquid located in the dishes 34 and 17 is vaporised.

In FIG. 3 the jacket 41 with its extension 42 forms a receiver dish 43 for sterilising liquid which with the aid of the nozzles 44 is sprayed on to the outside surfaces of the jacket 41. Inside the jacket is located the movable pipe 45 which with the aid of a mean such as the rod 46 can be moved upwards from the closed position shown in the drawing; the material to be filled, which is led through the line 47 into the space 48 defined in part by sealing means 48' between the jacket 41 and pipe 45, can then enter the interior of the pipe 45 through the lateral opening 49 and emerge through the passage between the external jacket 41 and the movable pipe 45 via a lateral opening 45' in the lower end of the pipe 45. For the preliminary sterilisation the sterilising liquid caught in the dish 43 is vaporised with the pipe 45 in the closed position shown by supplying heating medium through the pipe 47 into the interior of the pipe 45. The heating medium flows into the intermediate passage between the jacket 41 and the movable pipe 45 following the arrow 50 and is discharged via the line 51. The entire device projects into the interior of the flexible tube 52 being formed continuously from the plastics-coated paper web 53 by welding of the edges of the web. At the point 54 the flexible tube, which during operation is filled to the level 55 indicated by the dot-dash line, is welded transversely with the aid of welding jaws (not shown). With the aid of corresponding transverse welds lying in a plane at right angles to the welding 54, tetrahedral packs 56 are formed in known manner.

During the supply of heating medium into the annular passage between the jacket 41 and movable pipe 45 the receiver dish 43 is heated to the point where the sterilising liquid contained in it vaporises. The vapor formed sterilises the outside surfaces of the jacket 41, i.e. the filling pipe and, at the same time, the internal side of the flexible tube. After the sterilisation is complete the supply of heating medium through the line 47 is switched off, the line 47 is connected to the supply line for the sterile material to be filled and filled packages are formed by raising the rod 46 while the flexible tube 52 is travelling downwards. In the embodiment according to FIG. 3, too, an intermediate partition ring 57 is provided which comes to lie sealingly against the inner wall of the flexible tube of packaging material. As in the previously described embodiment, it collects and distributes the sterilising liquid over the periphery of the filling pipe. It prevents also the filling liquid splashing upwards during filling and/or during welding of the flexible tube.

Claims

We claim:

1. Apparatus for sterilising the outside of a filling pipe in an aseptic packaging machine, in which the filling pipe projects into the interior of a flexible tube being formed continuously from packaging material in web form, characterised in that the filling pipe is provided with a receiver dish for a vaporisable, chemically acting sterilising liquid at its lower end, with supply and distribution means for said liquid located around the periphery and above the end of the filling pipe and with means for vaporising the sterilising liquid in said dish.

2. Apparatus as claimed in claim 1, characterized in that said lower end of the filling pipe is double walled with outer and inner walls and in that a heating medium can be introduced into the annular space between the outer and inner walls, the heat given up from said heating medium being able to flow through the outer wall of the filling pipe into the receiver dish.

3. Apparatus as claimed in claim 1, characterized in that a partition is located above the receiver dish on the outside of the filling pipe for sealing against the flexible tube of packaging material.

4. In an aseptic packaging machine,

a filling pipe having a feed pipe for feeding material to be packaged and a jacket surrounding said feed pipe to define an annular space therebetween;

means for distributing sterilising liquid over said jacket on the exterior surface thereof;

a receiver dish at a lower end of said jacket for collecting sterilising liquid; and

means for heating said receiver dish from within said space to vaporize the sterilising liquid in said receiver dish.

5. In an aseptic packaging machine as set forth in claim 4, a partition on said surface of said jacket above said dish for collecting the sterilising liquid descending said surface and for redistributing the collected liquid over said jacket surface below said partition.

6. In an aseptic packaging machine as set forth in claim 4 wherein said means for distributing sterilising liquid includes nozzles located above said receiver dish.

7. In an aseptic packaging machine as set forth in claim 4 wherein said feed pipe is movably mounted in said jacket.

8. In an aseptic packaging machine

a filling pipe for feeding material to be packaged,

means for distributing sterilising liquid over said filling pipe on the exterior surface thereof,

a receiver dish on a lower end of said filling pipe for collecting sterilising liquid from said surface, and

means for heating said receiver dish to vaporize the sterilising liquid in said receiver dish.

9. In an aseptic packaging machine as set forth in claim 8 wherein said filling pipe includes an annular space therein adjacent said dish and said means for heating includes a pipe for feeding a heated medium into said space.

10. In an aseptic packaging machine as set forth in claim 8 wherein said filling pipe includes a jacket, a movable pipe in said jacket having a lateral opening therein, a stationary sealing means between said jacket and movable pipe to define a space between said jacket and said pipe, a line for feeding material through said jacket and into said space said lateral opening having a first position where said sealing means is located between said opening and said line preventing communication of said opening with said line, and a means for moving said movable pipe upwardly relative to said jacket and said sealing means to a second position to expose said opening to said line.

11. In an aseptic packaging machine as set forth in claim 10 wherein said movable pipe has a second lateral opening in a lower end for passage of material through said movable pipe into said space and out of a lower open end of said jacket.