How to choose the right thermocouple

Choose the thermocouple used according to the temperature range, the required accuracy, atmosphere, the performance of the measured object, response time and the economic benefits and other comprehensive consideration.

1, the choice of measurement precision and temperature measurement range

use temperature at 1300 ~ 1800 ℃, requirements and high accuracy, generally choose B type thermocouple; Required accuracy is not high, atmosphere and allow tungsten-rhenium thermal power

I are available, and higher than 1800 ℃ generally choose tungsten-rhenium thermocouples; Temperature at 1000 ~ 1300 ℃ requires accuracy and higher available S type thermocouple and N type thermocouple; Under 1000 ℃ K type thermocouple is commonly used in

and N type thermocouple, below 400 ℃ general use E type thermocouple; Negative temperature under 250 ℃, and usually measured in T thermocouple, T thermocouple during low temperature stability and high precision.

2, the choice of using atmosphere

S, type B, type K thermocouple is suitable for use in strong oxidation and weak reducing atmosphere, J type and T type thermocouple is suitable for weak oxidizing and reducing atmosphere, if use air tightness better protection tube, the atmosphere is not too strict.

3, durability and thermal response options

wire diameter of thermocouple better durability, but some response is slow, the heat capacity of thermocouple, response is slow, measure the gradient of temperature, in the case of temperature control, temperature control is poor. Requirements for fast response time and has certain durability requirements, choose armored even more appropriate.

4, the nature of the measured object and the state's choice of thermocouple

motion object, vibration, temperature measurement requirements of high mechanical strength, high pressure vessel with chemical pollution of the atmosphere requires protecting tube, with electrical interference requirements under the condition of the insulation is quite high.