Apparatus and methods for making differentially-conditioned package pairs

Abstract

Different products are hermetically sealed in separate but integrally adjoining packages to form package pairs or what might be called 'dual' packages. All of the packages are made from two continuous sheets of plastic packaging material, and the separate packages of each pair are differentially-conditioned by differential evacuation and/or gassing to different pressure levels. A continuous series of filled side-by-side containers formed from one sheet of packaging material is conveyed in two parallel rows into a sealing region where a cover sheet is laid over the containers to form packages. A group of the packages is stopped in the sealing region, and are clamped and partially sealed around the peripheries of the individual packages. The individual side-by-side units of the package pairs are differentially conditioned as to vacuum pressure or gas pressure or composition through aligned openings between adjacent containers in each of the parallel rows. The aligned openings and the remainder of the peripheries around the package then are sealed, and the completed package pairs are removed from the sealing region. The differential conditioning of the package pairs may be by way of differential evacuation, or evacuation followed by back-filling the packages with different pressures of gas, or other combinations.