| 摘要 |
PCT No. PCT/GB94/02324 Sec. 371 Date Jul. 3, 1996 Sec. 102(e) Date Jul. 3, 1996 PCT Filed Oct. 21, 1994 PCT Pub. No. WO95/11516 PCT Pub. Date Apr. 27, 1995A planar heating element for an electrically-heated water boiling vessel comprises a stainless steel plate having a printed heating element formed on one side thereof, the printed beating element being sandwiched between electrically-insulating layers of glass. A control for switching off the element in an overtemperature situation has a primary actuator in the form of a bimetal which directly accesses the printing element through a window formed in the outermost glass insulating layer, and the bimetal is held in a secondary actuator in the form of a thermally-collapsible carrier for the bimetal which contacts the glass insulation around the window. By virtue of this arrangement the primary and secondary actuators are subjected to different temperatures which ensures that the secondary actuator is not susceptible to nuisance operation. |
