Abstract: A pair of heat seal jaws (31, 32) for heat sealing together two heat sealable polymeric surfaces (33, 33'), the jaws (31, 32) including first sealing surfaces (36) which in use cooperate to produce at least one relatively strong heat seal between the said polymeric surfaces (33, 33') and second heat sealing surfaces (37, 38) which in use cooperate to produce at least one relatively weak but substantially hermetic heat seal between the polymeric surfaces, said first and second heat sealing surfaces being disposed relative to each other so that during heat sealing of the polymeric surfaces, polymer in the vicinity of the second heat sealing surfaces can flow away from the relatively weak seal to produce a substantially hermetic seal as the relatively weak seal is being formed.

Abstract: Form-fill-seal apparatus for simultaneously packaging two streams of articles (15), a sheet of packaging material (17) being brought around the adjacent articles (15), a central portion of the material (17) being passed between the streams of articles (15) and between outer edge portions of the packaging material (17). The packaging material (17) is sealed through the combined thicknesses of its central portion and its edge portions without introducing a sealing device between the articles (15). Adjacent packages can be separated by cutting through the central portion of the packaging material (17), for example using a blade (29) positioned along the line of flow of the articles (15). The present invention enables hitherto proposed single stream form-fill-seal apparatus to be modified relatively easily to enable twin streams of packages to be produced without increasing the speed of the packaging material or the linear speed of individual articles.