Methods and devices to determine a temperature with a thermocouple

A method to determine the temperature of a high temperature environment with a thermocouple, comprising:

• providing a thermocouple at a position p1 at a temperature T1, wherein the thermocouple comprises two thermowires, each comprising a measuring end and a cold end, wherein the thermowires are connected to each other at their measuring ends at a measuring junction;
• providing a temperature sensor configured to measure a temperature at position p1;
• measuring the temperature T1 with the temperature sensor at a point in time t1;
• measuring a voltage signal V1 of the thermocouple at the point in time t1;
• calculating the difference ΔV(t1) between the voltage signal, which would be obtained for a thermocouple with a cold junction at 0° C. and a measuring junction at temperature T1 V0° C.(T1), and the measured voltage signal V1;
• moving the thermocouple from position p1 to a second position p2 at a temperature T2 in the high temperature environment;
• measuring a voltage signal V2 of the thermocouple at a point in time t2;
• and,
• determining the temperature T2 of the high temperature environment at the point in time t2 based on the voltage signal V2 and the difference ΔV(t1) between the voltage signal, which would be obtained for a thermocouple with a cold junction at 0° C. and a measuring junction at temperature T1 V0° C.(T1), and the measured voltage signal V1 at the point in time t1.

A thermocouple system for determining the temperature of the cold junction of a thermocouple, comprising:

• a thermocouple at a position p1, wherein the thermocouple comprises two thermowires, each comprising a measuring end and a cold end, wherein the thermowires are connected to each other at their measuring ends at a measuring junction and wherein the cold ends are connected to a pair of connection means at a cold junction;
• II) a temperature sensor, wherein the temperature sensor is configured to measure the temperature at position p1;
• III) a pair of connection means, each comprising a cold junction connection end and an opposite end, wherein the cold ends of the thermowires are connected to the cold junction connection ends of the pair of connection means at the cold junction;
• and,
• IV) processing means, connected to the connection means at their opposite ends and configured to process a signal of the thermocouple and a signal of the temperature sensor to determine the temperature of the cold ends of the thermowires and/or configured to process a signal of the thermocouple and a signal of the temperature sensor and to calculate the difference ΔV between the voltage signal, which would be obtained for a thermocouple with a cold junction at 0° C. and a measuring junction at temperature T1 V0° C.(T1), and a measured voltage signal.