Method and a packaging apparatus for forming sealed partially-filled packages

1. A method for forming sealed partially-filled packages filled with a pourable product comprising at least:

forming a tube from a web of packaging material;

filling the pourable product into the tube for forming a product column within the tube;

directing a sterile gas into the product column for forming and/or maintaining a gas cushion within the product column which divides the product column into an upper portion and a lower portion;

forming and transversally sealing the tube, for obtaining the packages containing the pourable product and a gas space formed from a defined volume of the sterile gas originating from the gas cushion.

2. The method according to claim 1 , further comprising:

detecting and/or determining an elevation level of the product column;

controlling pressure of the sterile gas as a function of the elevation level.

3. The method according to claim 2 , wherein during the controlling of the pressure of the sterile gas, the pressure of the sterile gas is controlled such that the elevation level of the product column remains substantially constant.

4. The method according to claim 2 , wherein during the controlling of the pressure of the sterile gas, the pressure and/or flow of the sterile gas is controlled as a function of a size and/or a format of the packages.

5. The method according to claim 1 , wherein the forming and transversally sealing of the tube comprises transversally sealing the tube through a portion of the gas cushion for obtaining the gas space in the packages.

6. The method according to claim 1 , wherein during the directing of the sterile gas, pressure and/or flow of the sterile gas is controlled such that the volume of sterile gas present within the packages ranges between 1% to 35% of an overall inner volume of the packages.

7. The method according to claim 1 , wherein during the directing of the sterile gas into the product column, pressure of the sterile gas within the gas cushion is controlled between 5 kPa to 40 kPa above ambient pressure.

8. The method according to claim 1 , and further comprising at least controlling a pressure of an auxiliary sterile gas acting on the product column.

9. The method according to claim 8 , wherein, in use, a delimiting element is arranged within the tube and divides the tube into a first space and a second space;

wherein the second space contains the product column and during the controlling of the pressure of the auxiliary sterile gas, the auxiliary sterile gas is directed into a zone of the second space between the delimiting element and the product column.

10. The method according to claim 1 , and further comprising at least:

advancing the web of packaging material to a tube forming station at which the web of packaging material is formed into the tube; and

advancing the tube along a tube advancement path.

11. The method according to claim 1 , wherein during the directing of the sterile gas into the product column, the pressure of the sterile gas within the gas cushion is controlled between 10 kPa to 30 kPa above ambient pressure.

12. A packaging apparatus for forming sealed partially-filled packages filled with a pourable product comprising at least:

a tube forming and sealing device configured to form a tube from a web of packaging material and to longitudinally seal the tube;

a filling device adapted to direct, in use, a pourable product into the tube for obtaining a product column within the tube;

a gas feeding device configured to direct a sterile gas into the product column such that, in use, a gas cushion which divides the product column into an upper portion and a lower portion is formed and/or maintained within the product column;

a package forming unit for forming and transversally sealing the tube for obtaining the packages filled with the pourable product and containing a gas space containing a defined volume of the sterile gas present within the gas cushion.

13. The packaging apparatus according to claim 12 , wherein the gas feeding device comprises a level detection unit configured to detect and/or determine an elevation level of the product column; and

wherein the gas feeding device is configured to control pressure of the sterile gas as a function of the elevation level.

14. The packaging apparatus according to claim 12 , wherein the gas feeding device is configured to control pressure of the sterile gas such that the elevation level of the product column remains, in use, substantially constant.

15. The packaging apparatus according to claim 12 , wherein the package forming unit is so configured as to transversally seal the tube through a portion of the gas cushion for obtaining the gas space in the packages.

16. The packaging apparatus according to claim 12 , wherein the gas feeding device is configured to control pressure of the sterile gas as a function of a size and/or a format of the packages.

17. The packaging apparatus according to claim 12 , wherein the gas feeding device is configured to control a gas pressure of the sterile gas of the gas cushion to range between 5 kPa to 40 kPa above ambient pressure.

18. The packaging apparatus according to claim 12 , and further comprising at least a pressurizing device configured to control an auxiliary pressure of an auxiliary sterile gas acting on the product column.

19. The packaging apparatus according to claim 18 , and further comprising a delimiting element, in use, arranged within the tube for dividing the tube into a first space and a second space;

wherein the second space comprises the product column; and

wherein the pressurizing device ( 41 ) is configured to direct the auxiliary sterile gas into a zone of the second space between the delimiting element and the product column.

20. The packaging apparatus according to claim 12 , wherein the gas feeding device is configured to control a gas pressure of the sterile gas of the gas cushion to range between 10 kPa to 30 kPa above ambient pressure.