| 摘要 |
<p>The trays (1, 2, 3,...), inserted in tiered compartments, have designated hot food areas incorporating material (6, 10, 7) readily heated by induction and provided also (8, 9) within insulating plate-covers (11, 12). Above (28, 20, 25, 27,...) and below (19, 24, 26, 29,...) these areas lie induction coils, or coil groups, with field-control elements (21), e.g. radially disposed ferrite bars. Coil groups are energised singly, sequentially, each for e.g. 1 sec., from a common HF source (18), using a switching unit (35) and multiplexer (34). The groups may be switched in pairs i.e. upper and lower groups in each compartment. Unoccupied compartments are detected by a current monitor (30), which excludes them from the switching program.</p> |
