Fuente: WIPO "tomato" System (100) for heating a longitudinal edge of a packaging web advancing along an advancement path; the system (100) comprising an actuating apparatus (103) configured to adjust an air flow to be fed for heating a longitudinal edge of the packaging web The actuating apparatus (103) comprises: a valve (104) configured to adjust the air flow to be fed for heating the longitudinal edge of the packaging web; and an actuator (105) coupled to the valve and configured to adjust a position of the valve (104) to control the air flow based on at least one between a parameter (Δf, T, p) associated to the air flow and a parameter associated to the movement of the packaging web along the advancement path.