Fuente: WIPO "tomato" A packaging machine (1) for producing sealed packages from a web (4) of packaging material comprises : - a tube forming and sealing device (4) for folding said web (3) into a tube (5) and longitudinally sealing it, the forming and sealing device (4) comprising a heating element (40); - an isolation chamber (8), within which the heating element (40) is positioned; - a profile measurement sensor (12) facing the heating element (40) and configured to generate a sensor signal (S); and - a control unit (13) configured to detect a portion (40") of the heating element (40) as a function of the sensor signal (S).