| 摘要 |
Particularly in the case of tubular heating elements of electrically heated appliances, such as coffee machines, irons, washing machines, dishwashers or the like, the heating current must be interrupted after a regulator failure, before a critical temperature is exceeded. It is already known to make use of the change in conductivity of an inorganic substance as a sensor, using the temperature-dependent change of the unit condition. According to the invention, the substance forms a bridge (24, 34, 44, 54, 61, 71, 81) between lead connections (23, 25, 35, 37, 45, 46, 56, 62, 75, 82) in a shunt path in parallel with the live conductor (4, 7, 14, 52) so that, when the sensor responds, a current can flow which is sufficient for a switching function. In this case, the substance contains at least one salt, one acid or one base whose melting points are between approximately -120 DEG C and +1200 DEG C. A safety system is thus created which responds at specific and predeterminable temperatures of a conductor through which current flows, and which possibly operates in a reversible manner. <IMAGE>
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