| 摘要 |
This invention relates to a new type of electric kiln suitable for the firing of pottery in small batches as is customarily carried out by hobbyists. In its preferred form the invention comprises an upright cylindrical wall of ceramic fibre thermal insulation mounted on a thermally insulating base and fitted with a lid of similar insulating material. Located within the cylindrical wall is a heating element which is a single multiturn helix of resistance wire of helix diameter slightly smaller than the inner diameter of the cylindrical wall. The diameter of the resistance wire may be substantially greater (and the electrical resistance less) than is normally used in electric kilns of similar size thus permitting a greater tolerance to corrosion. The heating element is carried in a set of equispaced ceramic pillars which permit changes in the diameter of the helix while maintaining the separation of the turns of the helix. Matching to a source of alternating current is achieved by an electronic circuit which permits variable transformations of the voltage and current.
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