Patent ID: 6748726
Filing Date: 2004-06-15
Classification: B29C,B29L,B65B

Abstract:
A sealing device for a machine for packaging products under a controlled atmosphere in containers having an upper opening surrounded by a rim on which a sealing film is to be welded for sealing the container, said device comprising:a stationary top part forming a bell, said top part comprising a fixed one-piece circumferential wall having a lower free edge; a bottom part forming a pan having an upper free edge, for receiving at least one container to be sealed, said bottom part being vertically movable between a lower position and an upper position such that in said upper position, said free edges of said top and bottom parts directly engaging one another with said edge of said container therebetween, and said top and bottom parts defining a sealed enclosure around said container; and a welding head movably mounted through an opening in said top part so as to be within a space defined by said fixed one-piece circumferential wall, said welding head being movable vertically up and down between an upper retracted position above said edge of said container, and a lower welding position for welding said film on said edge of said container, said fixed one-piece circumferential wall comprising: means for feeding a continuous sealing film having a predetermined cross-section through a side of said fixed one-piece circumferential wall and over said opening of said container, said side of said fixed one-piece circumferential wall having a slot having an upper and a lower surface and a fixed cross-section greater than the cross-section of said film, said film passing between said upper and lower surfaces, said slot being above said lower free edge; an inflatable hose in said slot for closing said slot and immobilizing said film in said slot when actuated; and means for passing fluid through said fixed one-piece circumferential wall located between said slot and said lower free edge, so that fluid entering inside said enclosure enters between said edge of said container and said film, before said film is welded on said edge of said container by said welding head when said welding head is in said lower welding position, said fixed one-piece circumferential wall being fixed with respect to said means for passing fluid.