Method and apparatus for replacing air within a container head space

In an apparatus for sealing narrow-mouthed containers and replacing air remaining in the container head space with an inert gas, said apparatus including a filling machine, a star wheel device for transferring a container filled by the filling machine to sealing means, said sealing means having a downwardly directed sealing plunger for sealing each container, an ejecting device for transferring sealed containers away from the sealing means, said apparatus having means for blowing inert gas into the head space of each container, the improvement comprising:

• means disposed above said star wheel device for blowing a heated inert gas in the head space of each container and means disposed below said sealing plunger of said sealing machine, for blowing an inert gas into the head space of each container;
• said means disposed above said star wheel device comprising a bubble eliminating device having a semi-annular cover which extends along the path of the containers being moved by said star wheel device, said cover having sides which extend below the level of the tops of the containers to form an enclosed heated gas retaining space above and along the path of the containers, said semi-annular cover having only a single heated gas nozzle at a position near the entrance end of said bubble eliminating device, said single heated gas nozzle connected to a supply of heated gas for blowing heated gas into the head space of narrow-mouthed containers as they are transferred by said star wheel device to said sealing means, said cover being spaced sufficiently close to the narrow-mouthed containers for retaining heated gas from said single heated gas nozzle around the tops of the containers as they move through the remainder of said cover beyond said single heated gas nozzle, whereby bubbles are eliminated in the head space of the narrow-mouthed containers and the bubbles are replaced by heated gas due to a decrease in static pressure within the containers which is equivalent to the dynamic pressure produced in the vicinity of the narrow-mouthed portion of the containers due to the velocity of the containers being transferred through said cover by said star wheel transfer device, and
• said means disposed below said sealing plunger includes a single nozzle for blowing an inert gas into the head space of the containers while said sealing plunger of said sealing means is lowered to cover the narrow-mouthed portion of the containers with a sealing body.