| 摘要 |
PURPOSE:To contrive to reduce the number of spot welds for forming a waveguide by forming a structure wherein a groove, which opens to a heating chamber, is formed by partially swelling the wall of the heating chamber outside the heating chamber and the openings of the groove are covered by metal plates excluding feeder ports so as to use the interior of the groove as the waveguide. CONSTITUTION:Because the antenna 18 of a magnetron 16 faces to the interior of a groove 11 by loosely piercing a hole at a bent terminal face 3, microwaves proceed in the interior of the groove 11 as a waveguide so as to be supplied through the respective feeder ports 15a-15d into a heating chamber. In order to prevent microwaves from leaking through an opening 14, which locates outside the heating chamber, of the cruciform groove 11 outside, spot welds 19, 19... are applied at intervals of 15-30mm at the junction part of the bent initial face 2 and the bent terminal face 2 near the opening 14. On the other hand, because even if microwaves leak through the junction gap between a top wall 5 and a metal plate 13 at the periphery of the opening 12, which locates inside the heating chamber, the leakage microwaves are confined in the heating chamber, the junction part just mentioned above can serve well with spot welds 20, 20... applied at intervals larger than the intervals of the spot welds 19 and 19 and consequently the number of welds can be reduced.
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