Fecha de publicación: -- Fuente: WIPO "tomato" A packaging machine for forming a plurality of sealed packages comprises: a conveying device, configured to advance a web of packaging material; an isolation chamber; a tube forming device configured to form a tube from the advancing web of packaging material; a sealing device; a filling device; a package forming unit configured to form and transversally seal the packages from the advancing tube; a tensioning device; a control unit configured to control the conveying device and/or the tensioning device and/or the package forming unit so to vary an advancement speed of the tube.