Mixing device for foam-in-bag packaging system

A foam-in-bag packaging system is disclosed that comprises a mixing device for mixing foam precursors in a bag of flexible plastic film material sealed on all four sides by respective edge seals and having a plurality of frangible seals therein defining three separate interior cells in the bag. Two of the cells separately contain a first and second foam precursor composition and the cells are located at one end of the bag. The remainder of the bag is vented for permitting gases to escape from the bag as the foam precursors form foam while preventing foam or foam precursors from escaping from the bag. The mixing device ruptures the frangible seals to form a single interior cell and mixes the first and second foam precursors. The mixing device includes a cylindrical chamber to confine the one end portion of the bag containing the two cells with precursors therein, a clamp for clamping the bag adjacent these cells with the remainder of the bag projecting outwardly from the cylindrical chamber, and rollers within the chamber for rupturing the frangible seals and mixing the foam precursors within the one end portion of the bag while the clamp prevents the precursors from entering the remaining portion of the bag.