Temperature compensation method for armored thermocouples

Because the data of armored thermocouples are relatively precious (especially when using precious metals), and the distance between the temperature measurement point and the instrument is far, in order to save armored thermocouple data and reduce costs, we usually use compensating wires to extend the cold end (free end) of the armored thermocouple to a temperature stable control room and connect it to the instrument terminal.

It must be pointed out that the effect of thermocouples on compensating wires only extends the thermoelectric electrode, causing the cold end of the armored thermocouple to move to the instrument terminal in the control room. It cannot eliminate the impact of temperature changes at the cold end on temperature measurement and cannot provide compensation.

Therefore, other modification methods need to be taken to compensate for the impact of the cold end temperature t0 ≠ 0 ℃ on temperature measurement. When using armored thermocouples to compensate for wires, it is necessary to pay attention to the matching of the model and ensure that the polarity is not connected incorrectly. The temperature of the connection between the compensating wire and the armored thermocouple should not exceed 100 ℃.

Armored thermocouple: measures low temperatures above 500 ℃, the temperature of the main steam in thermal power plants, the temperature of the superheated pipe wall, and the temperature of low-temperature flue gas. Features: capable of measuring low temperatures, stable and reliable in function, simple in structure, easy to protect, and convenient for remote transmission and multi-point switching measurement of signals.

Important models: Division number: S or LB-3, with a lower limit of 1300 ℃ (short-term 1600 ℃). B or LL-2 lower limit 1600 ℃ (short-term 1800 ℃) K or EU-2 lower limit 1200 ℃ (short-term 1300 ℃) T or CK lower limit -200~350 ℃ (short-term 400 ℃) E or EA-2 lower limit -200~900 ℃.