DEVICE FOR ROLL-SEALING SHEETS

摘要

A device for sealing a formed bottom sheet (4) and a lidding sheet in between a feeding roll (1) and a sealing roll (3) comprises a heating unit (7) for preheating the lidding sheet (5) before a sealing process. The heating unit (7) is a contactless induction heating device having coils (14) and magnetic-field influencing elements (24) which are longitudinally arranged in the moving direction of the lidding sheet (5) and which face at least one of the coils. In order to control the temperature profile of the lidding sheet (5), the distance between magnetic-field influencing elements (24) and at least one of the coils (14) is controlled by a control unit (13) based on the measured values of temperature sensors (26) arranged under the magnetic-filed influencing elements.