US Patent 7002111 Electric warmer with a current sensor

The present invention relates to an electric warmer for heating a container by means of a heat transfer medium. The warmer comprises a jar into which the container can be inserted for heating, and an electric heating device comprising at least one resistance heating element for heating the heat transfer medium. To indicate an improved electric warmer of the above-mentioned type in which power can be supplied in a particularly efficient manner while the control device can be configured at particularly low costs at the same time, the warmer comprises a sensor element for measuring the current flowing through the resistance heating element during operation of the heating device, and a control unit configured in such a manner that it detects a typical change in the current flowing through the resistance heating element due to a change in the state of aggregation of the medium to be heated, and controls power supply to the resistance heating element in dependence upon the state of aggregation of the medium to be heated.