Vacuum packaging machinery and process

An apparatus for wrapping and vacuum packaging a substantially compressible commodity comprising

• means for supplying a substantially compressible commodity to a wrapping station;
• means for supplying flexible, air impermeable tubular wrapping material having opposed wall sections to said wrapping station from a continuous length source;
• means for enveloping said compressible commodity with said wrapping material at said wrapping station such that an unsealed open mouth of said wrapping material extends beyond said compressible commodity;
• means to sever said wrapping material enveloping said compressible commodity from said continuous length source and seal the bottom portion of said severed wrapping material to form a commodity-containing bag having a closed bottom and an open mouth;
• a vacuum packaging station including vacuum packaging means comprising a flexible air impermeable membrane and a substantially co-extensive opposed surface defining therebetween a commodity receiving area for receiving a commodity-containing bag, said membrane comprising a single, flexible, inwardly deformable sheet material positioned between and supported along its entire periphery by a membrane frame in a manner so as to provide an airtight joint between said membrane and said frame, one surface of said membrane facing said co-extensive opposed surface and an opposing surface of said membrane being in communication with ambient air;
• means for bringing said substantially co-extensive opposed surface and said membrane-supporting frame into sealing engagement with each other to form a vacuum chamber laterally defined by said opposed surface and said membrane and adapted to contain said open-mouthed commodity-containing bag and enable displacement of air from the bag to be effected, said periphery of said membrane being spaced from said opposed surface upon said frame being brought into sealing engagement with said opposed surface a distance sufficient to permit said membrane to deform inwardly toward said opposed surface upon evacuation of said chamber;
• means for advancing said commodity-containing bag to a position between said co-extensive opposed surface and said membrane;
• vacuum means for evacuating said chamber to cause inward deformation of said flexible membrane toward said opposed surface to cause displacement of air from said open-mouthed commodity-containing bag, said deformation commencing in the central portion of said membrane and subsequently progressing outwardly therefrom so as to reduce entrapment of air in the commodity-containing bag;
• and
• means for sealing said open mouth portion of said commodity-containing bag subsequent to the displacement of air from said bag.