摘要 |
Apparatus for inductively heating metal can lids (50) includes high-permeability , low-conductivity cores (10, 12, 14) having at least two magnetically opposite polar portions (20, 22, 24) both directed tow ard a conveyance path (16) for the can lids (50). High-frequency AC currents (68) are applied to the windings (60, 62, 64) of the cores (10, 12, 14), thereby inducing AC heating currents in the can lids (50) and heating them sufficiently to drive off moistur e. The cores (10, 12, 14) may be E-shaped, and may be disposed in modules at various longitudinal positions along the conveyance pa th (16). Closed-loop temperature control apparatus may also be included to prevent overheating of the can closures in the event of unintended stoppage of the production line. |