Abstract: A device for determining the temperature of a medium in a tube or in a container is disclosed. The device includes a measuring tube protruding into the medium and closed at the end facing the medium by a measuring tube base, a resistance-based temperature sensor as a main sensor, and a thermoelectric voltage-based temperature sensor as an auxiliary sensor, arranged within the measuring tube at a fixed offset relative to the main sensor. The main sensor and the auxiliary sensor transmit measurement values to an analysis/transmitter unit. If the amount of a difference between the measurement values of the main sensor and the auxiliary sensor exceeds a first specified threshold, a fault notification relating to the integrity of the device is generated in the analysis/transmitter unit.

Abstract: The invention relates to an apparatus for the calibration of a thermometer in situ, wherein the apparatus has a temperature sensor (S) for determining a temperature (T); wherein a reference element (K) is provided for calibrating the temperature sensor (S); wherein the reference element (K) at least partially comprises a ferroelectric material (D), which experiences a phase transformation at at least one predetermined temperature (TPh) in a temperature range relevant for calibrating the temperature sensor (S).

Abstract: The invention relates to an apparatus for the calibration of a thermometer in situ, wherein the apparatus has a temperature sensor (S) for determining a temperature (T); wherein a reference element (K) is provided for calibrating the temperature sensor (S); wherein the reference element (K) at least partially comprises a ferroelectric material (D), which experiences a phase transformation at least one predetermined temperature (TPh) in a temperature range relevant for calibrating the temperature sensor (S).

Abstract: The invention relates to an apparatus for the calibration of a thermometer in situ, wherein the apparatus has a temperature sensor (S) for determining a temperature (T); wherein a reference element (K) is provided for calibrating the temperature sensor (S); wherein the reference element (K) at least partially comprises a ferroelectric material (D), which experiences a phase transformation at least one predetermined temperature (TPh) in a temperature range relevant for calibrating the temperature sensor (S).