Expandable container having lid for providing headspace control in a food can

摘要

The invention relates to lids for cans for receiving foodstuff which are to be subjected to a thermal treatment above 50° C. as sterilization or at least pasteurization. The lid (1) has an annular ring (2) seamable to the can body which ring can be firmly and sealingly connected with the can body rim portion and a cover panel (3) which is sealingly disposed (13) to said ring. The annular ring comprises a flat web (6) that points towards a vertical central axis (8) of the lid and is axially outwardly inclined (11) with respect to a horizontal plane (15). The cover panel (3) is sealed to the flat inclined web by means of a radially outer ring band (3a). A central area (3b) that is surrounded by the ring band is axially inwardly preformed towards an interior in a dome or bowl-shaped fashion and thereby stabilized. After closing of the can, it is subjected to the thermal treatment. Upon a change in pressure (in the closed can) occurring during this thermal treatment the cover panel changes from the preformed position (3b) to an axially outwardly directed bowl/dome-shaped position (3b′). After cooling the closed can, the cover panel (3) returns—at least substantially exactly—into its preformed position.

主权项

1. A lid for a can body for receiving a foodstuff, wherein, after sealingly closing of the can body, the closed can is subjectable to a thermally treating pasteurization or sterilization process, the lid comprising:
an annular ring for firmly seaming to a can body edge portion and a plane or surface oriented cover panel disposed sealingly on the annular ring or affixable to the ring; wherein the annular ring comprises a flat web that extends towards a vertical central axis of the lid and is inclined at an angle with respect to a horizontal plane, the inclination is oriented upwards or axially outward of the can body; wherein the cover panel is sealingly affixed to the flat web, by a radially outer ring band, and a remaining central portion that is surrounded by the ring band is preformed axially towards an interior of the can as a bowl-shape and is for this reason stabilized in a manner so that the bowl-shaped cover panel, during an increase in pressure during one of sterilization and pasteurization, changes from the preformed first position to a second position that is bowl-shaped axially outwards, and automatically returns to the preformed first position after cooling.