| 摘要 |
Packaging structures for the microwave cooking of foodstuffs are described which are formed from laminates which have an outer polymeric film layer, an outer support layer and a thin layer of electroconductive material between the outer layers of a thickness effective to produce thermal energy when exposed to microwave radiation. The laminate also incorporated one or more additional layers of material which result in differential degrees of heating being obtained from the thin layer of electroconductive material upon exposure of the packaging structure to microwave radiation. Specific examples of a pot pie dish and a pizza heating board are described. An operating mechanism of a three-position switch having a contact-bearing main shaft comprises a switch closing and opening operating device, and an earthing device closing and opening operating device. The two devices comprise driving flange plates connected by a common spring capable of being loaded by rotation of either of the operating shafts and transmitting after they deadpoint has been reached a drive movement of these flange plates transmitted by articulated levers to a crank handle wedged onto the main shaft. All the operations are high-speed and the torque transmitted to the main shaft increases in the course of the operatingmovement. A locking device maintains the main shaft in the open position during the loading phase of the spring. Packaging structures for the microwave cooking of foodstuffs are described which are formed from laminates which have an outer polymeric film layer, an outer support layer and a thin layer of electroconductive material between the outer layers of a thickness effective to produce thermal energy when exposed to microwave radiation. The laminate also incorporated one or more additional layers of material which result in differential degrees of heating being obtained from the thin layer of electroconductive material upon exposure of the packaging structure to microwave radiation. Specific examples of a pot pie dish and a pizza heating board are described.
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