| 摘要 |
A form of electrical heating device, which is particularly applicable to hair driers but may also be useful in fan heaters or other electrical heaters for gaseous or other fluid media, comprises an insulating support plate around which a resistance heating wire is helically coiled with neighbouring turns of the coil offset to achieve improved heat exchange to the medium flowing over it and while allowing the device to be produced inexpensively and in a simple and trouble-free manner. The centers of the respective groups of turns which are similarly offset may lie on parallel lines or lines which converge along the length of the device. There may be two such groups or more, four for example. The turns are located in suitably dimensioned slots in the edges of the support plate; the wire may be bent into meander or sinuous form, in which case it can be made to grip the support plate in the region of the slots. A second support plate may be provided, to form a cruciform support, in order to improve the stability of the heater winding, the slots in the second plate also being dimensioned to suit the positions of the turns.
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