| 摘要 |
The immersion heater for an appliance includes a mounting plate, a metal sheathed electrical resistance heating element having two end portions which extend through and which are secured to the mounting plate, and a single fastening device for fixing the mounting plate to the body shell of the appliance. The fastening device comprises a threaded heat conductive stud secured to the mounting plate and a nut having a complementary thread. A raised part of the active portion of the heating element is directly secured to and only to the stud, such as by brazing. A bimetallic element is fixed directly to the stud on the outside of the body shell. The stud provides a heat conductive path between the heating element and the bimetallic element. The bimetallic element bends when the appliance is energized 'dry' or when the liquid has boiled down to the element and pushes a dolly overcenter to open a pair of contacts and de-energize the heating element. The appliance is, preferably, an electric kettle provided with a further bimetallic element which switches off the kettle when water therein boils.
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