STERILE PACKAGING OF FLUENT MATERIALS

Abstract

A method of forming individual tubes or sachets containing fluent material, and a packaging machine for doing so, are described. The side of the foil which will be in contact with the fluent material when the package is formed is exposed to plasma mist or aerosol form as the tube or sachet is formed from a strip of laminate material (1), which is folded about a former (2) into a closed tube or sachet which passes over the open end of a dispensing tube (3) from which the fluent material is dispensed. A mist of plasma is injected into the interior of the material tube as it is formed, extracted from the area once it has passed over the interior walls of the laminate tube. The dispensing tube may be surrounded by a cylindrical pipe (6) having an open end adjacent the dispensing tube and providing a tapered or stepped construction to a forming tube (2) about which the laminate is folded, enabling the mist to flow out of the open end of the pipe surrounding the dispensing tube (3) and then to reverse direction and flow past the laminate surface as the tube or sachet is formed and thus sterilise that surface before it comes into contact with the product in question.

Claims

1-4. (canceled)

5. A method of forming individual foil or laminate tubes or sachets containing fluent material using a packaging machine which is characterised by exposing the side of the foil or laminate from which the tubes are made, and which will be in contact with the fluent material when the tune or sachet is formed, to plasma in mist or aerosol form as the tube or sachet is formed on the packaging machine.

6. A packaging machine which is adapted to form packaging from a strip of foil or laminate material into a closed foil or laminate tube or sachet by folding the material about a dispensing tube from which fluent material is dispensed to fill the tube or sachet and which is characterised by means for injecting a mist of plasma into the interior of the foil or laminate tube or sachet as it is formed, and extracting the mist from the area once it has passed over the interior walls of the foil or laminate tube or sachet being formed.

7. A packaging machine according to claim 6 wherein the dispensing tube is surrounded with a cylindrical pipe having an open end adjacent the dispensing tube and providing a tapered or stepped construction to a forming tube about which the foil or laminate is folded, enabling the mist to flow out of the open end of the pipe surrounding the dispensing tube and then to reverse direction and flow past the foil or laminate surface as the foil or laminate tube or sachet is formed and thus sterilise the foil or laminate surface before it comes into contact with the fluent material.

8. A packaging machine according to claim 7 wherein the forming tube includes apertures through which the mist may be extracted.

Description

[0013] The invention is illustrated by way of example with reference to the accompanying drawing which shows diagrammatically a filling head on a filling machine modified in accordance with the invention.

[0014] Referring to that drawing:

[0015] In known fashion, a strip of laminate material 1 is fed downwardly as shown in the drawing and formed around a former 2 to form a tube. Located centrally and coaxially to former 2 is a filling tube 3. The product to be contained in the sealed packages is pumped into the upper end of tube 3 and emerges at the lower end of tube 3 in the form of a stream of fluent material 4. Downstream of the lower end of tube 3, the laminate tube is heat-sealed across, diagrammatically indicated as area 5, so as to leave below area 5 (and above the previous area 5, not shown) a sealed package 6. Individual packages may be made by transversely cutting across the seal areas 5, at the level indicated by A-A on the drawing.

[0016] In accordance with the invention, the filling tube 3 is surrounded by a tube 6 centred on the filling tube, to define an inner annular space between tube 3 and tube 6 and an outer annular space between tube 6 and the tube formed from the strip of laminate material 1.

[0017] The upper end of tube 6 is an inlet pipe 10 via which a plasma mist may be injected into the outer annular space between former 2 and tube 6 and then between the laminate material and tube 6. The mist flows down the outer annular space and then, because tube 6 terminates just above the outlet orifice of tube 3, it flows back up the outer annular space, thus passing over the entire interior wall area of the laminate which has been formed into a tube. At the top of tube 6 is an exhaust port 11 from which the mist is extracted. The outer surface of tube 6 has a helical ridge 12 (this may not be required on all packaging machines) on it which causes the mist to spiral around the interior of the laminate tube so as to ensure complete sterilisation of the interior wall of the laminate tube. This ridge may not be required for larger packages. The plasma inlet (10) and exhaust port (11) could be reversed so that the plasma inlet is (11) and extraction is through (10).

[0018] When running continuously, the speed at which the tube is lowered in the direction of arrow 15 on the drawing, and the rate at which the fluent material 4 is pumped from the end of tube 3, are adjusted so that the individual sachets are filled to the desired degree. The degree of sterilisation achieved will depend on the passage time over which the mist passes down over the interior wall of the recently formed laminate tube and in contact with its interior surface. This distance is denoted B in FIG. 1.

[0019] By way of example, we have found that if the machine is set to operate producing one package per second, each package being 120 mm long, then if the distance B is less than 500 mm, then the interior of the tube will be exposed to the mist for approximately five seconds. This provides satisfactory sterilisation.