| 摘要 |
Described herein is an electrical heating unit for smooth top cookers. The unit comprises a heating element in the form of a spiral coil of bare wire which has then been helically rolled together with a strip of flexible thermal and electrical insulation such as a ceramic paper around a central core. The resulting rolled structure is some-what analogous to a "Swiss roll". This structure rests on and is supported on a base layer of thermal and electrical insulation which is desirably dish-shaped and contained an outer metal pan for earthing and mechanical protection. The rolled structure is retained in its configuration and held against the base layer by a number of spoke-like members of heat resistant and electrically insulating material across the top of the element. |
