Form fill and seal packaging machine with replaceable forming neck

A machine for forming packages from plastic film, said machine including:

• a forming neck capable of receiving flat film and forming said film into a tube corresponding to a cylindrical portion of said forming neck with said forming neck being removably mounted to said machine and being interchangeable with a plurality of forming necks having cylindrical portions of different diameters;
• means for attaching closure strips to said film, said attaching means being disposed upstream of said forming neck, said closure strip attaching means being of a sufficient length to attach closure strips having a length of up to half the circumference of a largest cylindrical portion of said forming neck;
• means for joining the longitudinal edges of said flat film;
• and means for transversely sealing said tube to form a package having a front, back and sides, said transverse sealing means producing a weld along a length equal to at least half the circumference of the largest cylindrical portion of said forming neck to weld said closure strips to said package front and back and to weld said package front to said package back from respective ends of said closure strips to respective package sides;
• thereby forming a seal between said closure strips respective ends and said package sides.