| 摘要 |
Tubular wrappings (2), formed from a sheet (4) with superimposed longitudinal lateral portions (4a, 4b) and made of partly metal (5) and partly heat-sealable (6) material, are sealed longitudinally by successively feeding the wrappings (2), by means of a conveyor (7), in a first given direction (8) and along a given path (9) through a sealing station (10); by varying the traveling speed of the wrappings (2) in relation to the conveyor (7) so as to successively impart to the wrappings (2) a pause at the sealing station (10); and by induction heating, for an adjustable length of time during the relative pause, the metal part (5) of the sheet (4) of each wrapping (2) along the relative superimposed longitudinal lateral portions (4a, 4b), to melt the heat-sealable part (6) of the sheet (4). <IMAGE> |
