| 摘要 |
<p>A method and apparatus for sealing a flat lid (L) with a lower layer of heat bondable material onto the upper, generally flat surface of a flange extending around the periphery of an access opening in a container (C) the type used to store a substance susceptible to deterioration when exposed to atmosphere for a prolonged time such as prepared foods, which method and apparatus moves a separate and distinct heating unit (H) with a downwardly facing heating ring (560) in a preselected path, preferably circular in shape, between first and second positions, includes a generally fixed high frequency power supply (180) for energizing said heating ring, connects this fixed high frequency power supply (180) to the individual heating rings (560) of the moving heating unit only when the unit is moving between the first and second positions, and energizes the power supply (180) only while the heating unit is moving between the first and second positions. The ring is forced against the lid (L) as the power supply (180) is energized and is released from the lid (L) after the power supply (180) has been de-energized and before the moving heating unit (H) reaches the second position. Preferably the ring (560) is an inductor and the plurality of heating units (H) are carried by a turret (T) to define individual heating stations (S1-S16) on the turret (T) which stations rotate to selectively energize the individual heating units (H) by the single fixed high frequency power supply (180) whereby single power supply (180) energizes a plurality of separate heating stations (H).</p> |
